Problem: Jzzhu has picked n apples from his big apple tree. All the apples are numbered from 1 to n. Now he wants to sell them to an apple store. 

Jzzhu will pack his apples into groups and then sell them. Each group must contain two apples, and the greatest common divisor of numbers of the apples in each group must be greater than 1. Of course, each apple can be part of at most one group.

Jzzhu wonders how to get the maximum possible number of groups. Can you help him?

Input

A single integer n (1 ≤ n ≤ 105), the number of the apples.

Output

The first line must contain a single integer m, representing the maximum number of groups he can get. Each of the next m lines must contain two integers — the numbers of apples in the current group.

If there are several optimal answers you can print any of them.

Examples

Input

6


Output

2
6 3
2 4


Input

9


Output

3
9 3
2 4
6 8


Input

2


Output

0

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int primes[] = {
    2,     3,     5,     7,     11,    13,    17,    19,    23,    29,    31,
    37,    41,    43,    47,    53,    59,    61,    67,    71,    73,    79,
    83,    89,    97,    101,   103,   107,   109,   113,   127,   131,   137,
    139,   149,   151,   157,   163,   167,   173,   179,   181,   191,   193,
    197,   199,   211,   223,   227,   229,   233,   239,   241,   251,   257,
    263,   269,   271,   277,   281,   283,   293,   307,   311,   313,   317,
    331,   337,   347,   349,   353,   359,   367,   373,   379,   383,   389,
    397,   401,   409,   419,   421,   431,   433,   439,   443,   449,   457,
    461,   463,   467,   479,   487,   491,   499,   503,   509,   521,   523,
    541,   547,   557,   563,   569,   571,   577,   587,   593,   599,   601,
    607,   613,   617,   619,   631,   641,   643,   647,   653,   659,   661,
    673,   677,   683,   691,   701,   709,   719,   727,   733,   739,   743,
    751,   757,   761,   769,   773,   787,   797,   809,   811,   821,   823,
    827,   829,   839,   853,   857,   859,   863,   877,   881,   883,   887,
    907,   911,   919,   929,   937,   941,   947,   953,   967,   971,   977,
    983,   991,   997,   1009,  1013,  1019,  1021,  1031,  1033,  1039,  1049,
    1051,  1061,  1063,  1069,  1087,  1091,  1093,  1097,  1103,  1109,  1117,
    1123,  1129,  1151,  1153,  1163,  1171,  1181,  1187,  1193,  1201,  1213,
    1217,  1223,  1229,  1231,  1237,  1249,  1259,  1277,  1279,  1283,  1289,
    1291,  1297,  1301,  1303,  1307,  1319,  1321,  1327,  1361,  1367,  1373,
    1381,  1399,  1409,  1423,  1427,  1429,  1433,  1439,  1447,  1451,  1453,
    1459,  1471,  1481,  1483,  1487,  1489,  1493,  1499,  1511,  1523,  1531,
    1543,  1549,  1553,  1559,  1567,  1571,  1579,  1583,  1597,  1601,  1607,
    1609,  1613,  1619,  1621,  1627,  1637,  1657,  1663,  1667,  1669,  1693,
    1697,  1699,  1709,  1721,  1723,  1733,  1741,  1747,  1753,  1759,  1777,
    1783,  1787,  1789,  1801,  1811,  1823,  1831,  1847,  1861,  1867,  1871,
    1873,  1877,  1879,  1889,  1901,  1907,  1913,  1931,  1933,  1949,  1951,
    1973,  1979,  1987,  1993,  1997,  1999,  2003,  2011,  2017,  2027,  2029,
    2039,  2053,  2063,  2069,  2081,  2083,  2087,  2089,  2099,  2111,  2113,
    2129,  2131,  2137,  2141,  2143,  2153,  2161,  2179,  2203,  2207,  2213,
    2221,  2237,  2239,  2243,  2251,  2267,  2269,  2273,  2281,  2287,  2293,
    2297,  2309,  2311,  2333,  2339,  2341,  2347,  2351,  2357,  2371,  2377,
    2381,  2383,  2389,  2393,  2399,  2411,  2417,  2423,  2437,  2441,  2447,
    2459,  2467,  2473,  2477,  2503,  2521,  2531,  2539,  2543,  2549,  2551,
    2557,  2579,  2591,  2593,  2609,  2617,  2621,  2633,  2647,  2657,  2659,
    2663,  2671,  2677,  2683,  2687,  2689,  2693,  2699,  2707,  2711,  2713,
    2719,  2729,  2731,  2741,  2749,  2753,  2767,  2777,  2789,  2791,  2797,
    2801,  2803,  2819,  2833,  2837,  2843,  2851,  2857,  2861,  2879,  2887,
    2897,  2903,  2909,  2917,  2927,  2939,  2953,  2957,  2963,  2969,  2971,
    2999,  3001,  3011,  3019,  3023,  3037,  3041,  3049,  3061,  3067,  3079,
    3083,  3089,  3109,  3119,  3121,  3137,  3163,  3167,  3169,  3181,  3187,
    3191,  3203,  3209,  3217,  3221,  3229,  3251,  3253,  3257,  3259,  3271,
    3299,  3301,  3307,  3313,  3319,  3323,  3329,  3331,  3343,  3347,  3359,
    3361,  3371,  3373,  3389,  3391,  3407,  3413,  3433,  3449,  3457,  3461,
    3463,  3467,  3469,  3491,  3499,  3511,  3517,  3527,  3529,  3533,  3539,
    3541,  3547,  3557,  3559,  3571,  3581,  3583,  3593,  3607,  3613,  3617,
    3623,  3631,  3637,  3643,  3659,  3671,  3673,  3677,  3691,  3697,  3701,
    3709,  3719,  3727,  3733,  3739,  3761,  3767,  3769,  3779,  3793,  3797,
    3803,  3821,  3823,  3833,  3847,  3851,  3853,  3863,  3877,  3881,  3889,
    3907,  3911,  3917,  3919,  3923,  3929,  3931,  3943,  3947,  3967,  3989,
    4001,  4003,  4007,  4013,  4019,  4021,  4027,  4049,  4051,  4057,  4073,
    4079,  4091,  4093,  4099,  4111,  4127,  4129,  4133,  4139,  4153,  4157,
    4159,  4177,  4201,  4211,  4217,  4219,  4229,  4231,  4241,  4243,  4253,
    4259,  4261,  4271,  4273,  4283,  4289,  4297,  4327,  4337,  4339,  4349,
    4357,  4363,  4373,  4391,  4397,  4409,  4421,  4423,  4441,  4447,  4451,
    4457,  4463,  4481,  4483,  4493,  4507,  4513,  4517,  4519,  4523,  4547,
    4549,  4561,  4567,  4583,  4591,  4597,  4603,  4621,  4637,  4639,  4643,
    4649,  4651,  4657,  4663,  4673,  4679,  4691,  4703,  4721,  4723,  4729,
    4733,  4751,  4759,  4783,  4787,  4789,  4793,  4799,  4801,  4813,  4817,
    4831,  4861,  4871,  4877,  4889,  4903,  4909,  4919,  4931,  4933,  4937,
    4943,  4951,  4957,  4967,  4969,  4973,  4987,  4993,  4999,  5003,  5009,
    5011,  5021,  5023,  5039,  5051,  5059,  5077,  5081,  5087,  5099,  5101,
    5107,  5113,  5119,  5147,  5153,  5167,  5171,  5179,  5189,  5197,  5209,
    5227,  5231,  5233,  5237,  5261,  5273,  5279,  5281,  5297,  5303,  5309,
    5323,  5333,  5347,  5351,  5381,  5387,  5393,  5399,  5407,  5413,  5417,
    5419,  5431,  5437,  5441,  5443,  5449,  5471,  5477,  5479,  5483,  5501,
    5503,  5507,  5519,  5521,  5527,  5531,  5557,  5563,  5569,  5573,  5581,
    5591,  5623,  5639,  5641,  5647,  5651,  5653,  5657,  5659,  5669,  5683,
    5689,  5693,  5701,  5711,  5717,  5737,  5741,  5743,  5749,  5779,  5783,
    5791,  5801,  5807,  5813,  5821,  5827,  5839,  5843,  5849,  5851,  5857,
    5861,  5867,  5869,  5879,  5881,  5897,  5903,  5923,  5927,  5939,  5953,
    5981,  5987,  6007,  6011,  6029,  6037,  6043,  6047,  6053,  6067,  6073,
    6079,  6089,  6091,  6101,  6113,  6121,  6131,  6133,  6143,  6151,  6163,
    6173,  6197,  6199,  6203,  6211,  6217,  6221,  6229,  6247,  6257,  6263,
    6269,  6271,  6277,  6287,  6299,  6301,  6311,  6317,  6323,  6329,  6337,
    6343,  6353,  6359,  6361,  6367,  6373,  6379,  6389,  6397,  6421,  6427,
    6449,  6451,  6469,  6473,  6481,  6491,  6521,  6529,  6547,  6551,  6553,
    6563,  6569,  6571,  6577,  6581,  6599,  6607,  6619,  6637,  6653,  6659,
    6661,  6673,  6679,  6689,  6691,  6701,  6703,  6709,  6719,  6733,  6737,
    6761,  6763,  6779,  6781,  6791,  6793,  6803,  6823,  6827,  6829,  6833,
    6841,  6857,  6863,  6869,  6871,  6883,  6899,  6907,  6911,  6917,  6947,
    6949,  6959,  6961,  6967,  6971,  6977,  6983,  6991,  6997,  7001,  7013,
    7019,  7027,  7039,  7043,  7057,  7069,  7079,  7103,  7109,  7121,  7127,
    7129,  7151,  7159,  7177,  7187,  7193,  7207,  7211,  7213,  7219,  7229,
    7237,  7243,  7247,  7253,  7283,  7297,  7307,  7309,  7321,  7331,  7333,
    7349,  7351,  7369,  7393,  7411,  7417,  7433,  7451,  7457,  7459,  7477,
    7481,  7487,  7489,  7499,  7507,  7517,  7523,  7529,  7537,  7541,  7547,
    7549,  7559,  7561,  7573,  7577,  7583,  7589,  7591,  7603,  7607,  7621,
    7639,  7643,  7649,  7669,  7673,  7681,  7687,  7691,  7699,  7703,  7717,
    7723,  7727,  7741,  7753,  7757,  7759,  7789,  7793,  7817,  7823,  7829,
    7841,  7853,  7867,  7873,  7877,  7879,  7883,  7901,  7907,  7919,  7927,
    7933,  7937,  7949,  7951,  7963,  7993,  8009,  8011,  8017,  8039,  8053,
    8059,  8069,  8081,  8087,  8089,  8093,  8101,  8111,  8117,  8123,  8147,
    8161,  8167,  8171,  8179,  8191,  8209,  8219,  8221,  8231,  8233,  8237,
    8243,  8263,  8269,  8273,  8287,  8291,  8293,  8297,  8311,  8317,  8329,
    8353,  8363,  8369,  8377,  8387,  8389,  8419,  8423,  8429,  8431,  8443,
    8447,  8461,  8467,  8501,  8513,  8521,  8527,  8537,  8539,  8543,  8563,
    8573,  8581,  8597,  8599,  8609,  8623,  8627,  8629,  8641,  8647,  8663,
    8669,  8677,  8681,  8689,  8693,  8699,  8707,  8713,  8719,  8731,  8737,
    8741,  8747,  8753,  8761,  8779,  8783,  8803,  8807,  8819,  8821,  8831,
    8837,  8839,  8849,  8861,  8863,  8867,  8887,  8893,  8923,  8929,  8933,
    8941,  8951,  8963,  8969,  8971,  8999,  9001,  9007,  9011,  9013,  9029,
    9041,  9043,  9049,  9059,  9067,  9091,  9103,  9109,  9127,  9133,  9137,
    9151,  9157,  9161,  9173,  9181,  9187,  9199,  9203,  9209,  9221,  9227,
    9239,  9241,  9257,  9277,  9281,  9283,  9293,  9311,  9319,  9323,  9337,
    9341,  9343,  9349,  9371,  9377,  9391,  9397,  9403,  9413,  9419,  9421,
    9431,  9433,  9437,  9439,  9461,  9463,  9467,  9473,  9479,  9491,  9497,
    9511,  9521,  9533,  9539,  9547,  9551,  9587,  9601,  9613,  9619,  9623,
    9629,  9631,  9643,  9649,  9661,  9677,  9679,  9689,  9697,  9719,  9721,
    9733,  9739,  9743,  9749,  9767,  9769,  9781,  9787,  9791,  9803,  9811,
    9817,  9829,  9833,  9839,  9851,  9857,  9859,  9871,  9883,  9887,  9901,
    9907,  9923,  9929,  9931,  9941,  9949,  9967,  9973,  10007, 10009, 10037,
    10039, 10061, 10067, 10069, 10079, 10091, 10093, 10099, 10103, 10111, 10133,
    10139, 10141, 10151, 10159, 10163, 10169, 10177, 10181, 10193, 10211, 10223,
    10243, 10247, 10253, 10259, 10267, 10271, 10273, 10289, 10301, 10303, 10313,
    10321, 10331, 10333, 10337, 10343, 10357, 10369, 10391, 10399, 10427, 10429,
    10433, 10453, 10457, 10459, 10463, 10477, 10487, 10499, 10501, 10513, 10529,
    10531, 10559, 10567, 10589, 10597, 10601, 10607, 10613, 10627, 10631, 10639,
    10651, 10657, 10663, 10667, 10687, 10691, 10709, 10711, 10723, 10729, 10733,
    10739, 10753, 10771, 10781, 10789, 10799, 10831, 10837, 10847, 10853, 10859,
    10861, 10867, 10883, 10889, 10891, 10903, 10909, 10937, 10939, 10949, 10957,
    10973, 10979, 10987, 10993, 11003, 11027, 11047, 11057, 11059, 11069, 11071,
    11083, 11087, 11093, 11113, 11117, 11119, 11131, 11149, 11159, 11161, 11171,
    11173, 11177, 11197, 11213, 11239, 11243, 11251, 11257, 11261, 11273, 11279,
    11287, 11299, 11311, 11317, 11321, 11329, 11351, 11353, 11369, 11383, 11393,
    11399, 11411, 11423, 11437, 11443, 11447, 11467, 11471, 11483, 11489, 11491,
    11497, 11503, 11519, 11527, 11549, 11551, 11579, 11587, 11593, 11597, 11617,
    11621, 11633, 11657, 11677, 11681, 11689, 11699, 11701, 11717, 11719, 11731,
    11743, 11777, 11779, 11783, 11789, 11801, 11807, 11813, 11821, 11827, 11831,
    11833, 11839, 11863, 11867, 11887, 11897, 11903, 11909, 11923, 11927, 11933,
    11939, 11941, 11953, 11959, 11969, 11971, 11981, 11987, 12007, 12011, 12037,
    12041, 12043, 12049, 12071, 12073, 12097, 12101, 12107, 12109, 12113, 12119,
    12143, 12149, 12157, 12161, 12163, 12197, 12203, 12211, 12227, 12239, 12241,
    12251, 12253, 12263, 12269, 12277, 12281, 12289, 12301, 12323, 12329, 12343,
    12347, 12373, 12377, 12379, 12391, 12401, 12409, 12413, 12421, 12433, 12437,
    12451, 12457, 12473, 12479, 12487, 12491, 12497, 12503, 12511, 12517, 12527,
    12539, 12541, 12547, 12553, 12569, 12577, 12583, 12589, 12601, 12611, 12613,
    12619, 12637, 12641, 12647, 12653, 12659, 12671, 12689, 12697, 12703, 12713,
    12721, 12739, 12743, 12757, 12763, 12781, 12791, 12799, 12809, 12821, 12823,
    12829, 12841, 12853, 12889, 12893, 12899, 12907, 12911, 12917, 12919, 12923,
    12941, 12953, 12959, 12967, 12973, 12979, 12983, 13001, 13003, 13007, 13009,
    13033, 13037, 13043, 13049, 13063, 13093, 13099, 13103, 13109, 13121, 13127,
    13147, 13151, 13159, 13163, 13171, 13177, 13183, 13187, 13217, 13219, 13229,
    13241, 13249, 13259, 13267, 13291, 13297, 13309, 13313, 13327, 13331, 13337,
    13339, 13367, 13381, 13397, 13399, 13411, 13417, 13421, 13441, 13451, 13457,
    13463, 13469, 13477, 13487, 13499, 13513, 13523, 13537, 13553, 13567, 13577,
    13591, 13597, 13613, 13619, 13627, 13633, 13649, 13669, 13679, 13681, 13687,
    13691, 13693, 13697, 13709, 13711, 13721, 13723, 13729, 13751, 13757, 13759,
    13763, 13781, 13789, 13799, 13807, 13829, 13831, 13841, 13859, 13873, 13877,
    13879, 13883, 13901, 13903, 13907, 13913, 13921, 13931, 13933, 13963, 13967,
    13997, 13999, 14009, 14011, 14029, 14033, 14051, 14057, 14071, 14081, 14083,
    14087, 14107, 14143, 14149, 14153, 14159, 14173, 14177, 14197, 14207, 14221,
    14243, 14249, 14251, 14281, 14293, 14303, 14321, 14323, 14327, 14341, 14347,
    14369, 14387, 14389, 14401, 14407, 14411, 14419, 14423, 14431, 14437, 14447,
    14449, 14461, 14479, 14489, 14503, 14519, 14533, 14537, 14543, 14549, 14551,
    14557, 14561, 14563, 14591, 14593, 14621, 14627, 14629, 14633, 14639, 14653,
    14657, 14669, 14683, 14699, 14713, 14717, 14723, 14731, 14737, 14741, 14747,
    14753, 14759, 14767, 14771, 14779, 14783, 14797, 14813, 14821, 14827, 14831,
    14843, 14851, 14867, 14869, 14879, 14887, 14891, 14897, 14923, 14929, 14939,
    14947, 14951, 14957, 14969, 14983, 15013, 15017, 15031, 15053, 15061, 15073,
    15077, 15083, 15091, 15101, 15107, 15121, 15131, 15137, 15139, 15149, 15161,
    15173, 15187, 15193, 15199, 15217, 15227, 15233, 15241, 15259, 15263, 15269,
    15271, 15277, 15287, 15289, 15299, 15307, 15313, 15319, 15329, 15331, 15349,
    15359, 15361, 15373, 15377, 15383, 15391, 15401, 15413, 15427, 15439, 15443,
    15451, 15461, 15467, 15473, 15493, 15497, 15511, 15527, 15541, 15551, 15559,
    15569, 15581, 15583, 15601, 15607, 15619, 15629, 15641, 15643, 15647, 15649,
    15661, 15667, 15671, 15679, 15683, 15727, 15731, 15733, 15737, 15739, 15749,
    15761, 15767, 15773, 15787, 15791, 15797, 15803, 15809, 15817, 15823, 15859,
    15877, 15881, 15887, 15889, 15901, 15907, 15913, 15919, 15923, 15937, 15959,
    15971, 15973, 15991, 16001, 16007, 16033, 16057, 16061, 16063, 16067, 16069,
    16073, 16087, 16091, 16097, 16103, 16111, 16127, 16139, 16141, 16183, 16187,
    16189, 16193, 16217, 16223, 16229, 16231, 16249, 16253, 16267, 16273, 16301,
    16319, 16333, 16339, 16349, 16361, 16363, 16369, 16381, 16411, 16417, 16421,
    16427, 16433, 16447, 16451, 16453, 16477, 16481, 16487, 16493, 16519, 16529,
    16547, 16553, 16561, 16567, 16573, 16603, 16607, 16619, 16631, 16633, 16649,
    16651, 16657, 16661, 16673, 16691, 16693, 16699, 16703, 16729, 16741, 16747,
    16759, 16763, 16787, 16811, 16823, 16829, 16831, 16843, 16871, 16879, 16883,
    16889, 16901, 16903, 16921, 16927, 16931, 16937, 16943, 16963, 16979, 16981,
    16987, 16993, 17011, 17021, 17027, 17029, 17033, 17041, 17047, 17053, 17077,
    17093, 17099, 17107, 17117, 17123, 17137, 17159, 17167, 17183, 17189, 17191,
    17203, 17207, 17209, 17231, 17239, 17257, 17291, 17293, 17299, 17317, 17321,
    17327, 17333, 17341, 17351, 17359, 17377, 17383, 17387, 17389, 17393, 17401,
    17417, 17419, 17431, 17443, 17449, 17467, 17471, 17477, 17483, 17489, 17491,
    17497, 17509, 17519, 17539, 17551, 17569, 17573, 17579, 17581, 17597, 17599,
    17609, 17623, 17627, 17657, 17659, 17669, 17681, 17683, 17707, 17713, 17729,
    17737, 17747, 17749, 17761, 17783, 17789, 17791, 17807, 17827, 17837, 17839,
    17851, 17863, 17881, 17891, 17903, 17909, 17911, 17921, 17923, 17929, 17939,
    17957, 17959, 17971, 17977, 17981, 17987, 17989, 18013, 18041, 18043, 18047,
    18049, 18059, 18061, 18077, 18089, 18097, 18119, 18121, 18127, 18131, 18133,
    18143, 18149, 18169, 18181, 18191, 18199, 18211, 18217, 18223, 18229, 18233,
    18251, 18253, 18257, 18269, 18287, 18289, 18301, 18307, 18311, 18313, 18329,
    18341, 18353, 18367, 18371, 18379, 18397, 18401, 18413, 18427, 18433, 18439,
    18443, 18451, 18457, 18461, 18481, 18493, 18503, 18517, 18521, 18523, 18539,
    18541, 18553, 18583, 18587, 18593, 18617, 18637, 18661, 18671, 18679, 18691,
    18701, 18713, 18719, 18731, 18743, 18749, 18757, 18773, 18787, 18793, 18797,
    18803, 18839, 18859, 18869, 18899, 18911, 18913, 18917, 18919, 18947, 18959,
    18973, 18979, 19001, 19009, 19013, 19031, 19037, 19051, 19069, 19073, 19079,
    19081, 19087, 19121, 19139, 19141, 19157, 19163, 19181, 19183, 19207, 19211,
    19213, 19219, 19231, 19237, 19249, 19259, 19267, 19273, 19289, 19301, 19309,
    19319, 19333, 19373, 19379, 19381, 19387, 19391, 19403, 19417, 19421, 19423,
    19427, 19429, 19433, 19441, 19447, 19457, 19463, 19469, 19471, 19477, 19483,
    19489, 19501, 19507, 19531, 19541, 19543, 19553, 19559, 19571, 19577, 19583,
    19597, 19603, 19609, 19661, 19681, 19687, 19697, 19699, 19709, 19717, 19727,
    19739, 19751, 19753, 19759, 19763, 19777, 19793, 19801, 19813, 19819, 19841,
    19843, 19853, 19861, 19867, 19889, 19891, 19913, 19919, 19927, 19937, 19949,
    19961, 19963, 19973, 19979, 19991, 19993, 19997, 20011, 20021, 20023, 20029,
    20047, 20051, 20063, 20071, 20089, 20101, 20107, 20113, 20117, 20123, 20129,
    20143, 20147, 20149, 20161, 20173, 20177, 20183, 20201, 20219, 20231, 20233,
    20249, 20261, 20269, 20287, 20297, 20323, 20327, 20333, 20341, 20347, 20353,
    20357, 20359, 20369, 20389, 20393, 20399, 20407, 20411, 20431, 20441, 20443,
    20477, 20479, 20483, 20507, 20509, 20521, 20533, 20543, 20549, 20551, 20563,
    20593, 20599, 20611, 20627, 20639, 20641, 20663, 20681, 20693, 20707, 20717,
    20719, 20731, 20743, 20747, 20749, 20753, 20759, 20771, 20773, 20789, 20807,
    20809, 20849, 20857, 20873, 20879, 20887, 20897, 20899, 20903, 20921, 20929,
    20939, 20947, 20959, 20963, 20981, 20983, 21001, 21011, 21013, 21017, 21019,
    21023, 21031, 21059, 21061, 21067, 21089, 21101, 21107, 21121, 21139, 21143,
    21149, 21157, 21163, 21169, 21179, 21187, 21191, 21193, 21211, 21221, 21227,
    21247, 21269, 21277, 21283, 21313, 21317, 21319, 21323, 21341, 21347, 21377,
    21379, 21383, 21391, 21397, 21401, 21407, 21419, 21433, 21467, 21481, 21487,
    21491, 21493, 21499, 21503, 21517, 21521, 21523, 21529, 21557, 21559, 21563,
    21569, 21577, 21587, 21589, 21599, 21601, 21611, 21613, 21617, 21647, 21649,
    21661, 21673, 21683, 21701, 21713, 21727, 21737, 21739, 21751, 21757, 21767,
    21773, 21787, 21799, 21803, 21817, 21821, 21839, 21841, 21851, 21859, 21863,
    21871, 21881, 21893, 21911, 21929, 21937, 21943, 21961, 21977, 21991, 21997,
    22003, 22013, 22027, 22031, 22037, 22039, 22051, 22063, 22067, 22073, 22079,
    22091, 22093, 22109, 22111, 22123, 22129, 22133, 22147, 22153, 22157, 22159,
    22171, 22189, 22193, 22229, 22247, 22259, 22271, 22273, 22277, 22279, 22283,
    22291, 22303, 22307, 22343, 22349, 22367, 22369, 22381, 22391, 22397, 22409,
    22433, 22441, 22447, 22453, 22469, 22481, 22483, 22501, 22511, 22531, 22541,
    22543, 22549, 22567, 22571, 22573, 22613, 22619, 22621, 22637, 22639, 22643,
    22651, 22669, 22679, 22691, 22697, 22699, 22709, 22717, 22721, 22727, 22739,
    22741, 22751, 22769, 22777, 22783, 22787, 22807, 22811, 22817, 22853, 22859,
    22861, 22871, 22877, 22901, 22907, 22921, 22937, 22943, 22961, 22963, 22973,
    22993, 23003, 23011, 23017, 23021, 23027, 23029, 23039, 23041, 23053, 23057,
    23059, 23063, 23071, 23081, 23087, 23099, 23117, 23131, 23143, 23159, 23167,
    23173, 23189, 23197, 23201, 23203, 23209, 23227, 23251, 23269, 23279, 23291,
    23293, 23297, 23311, 23321, 23327, 23333, 23339, 23357, 23369, 23371, 23399,
    23417, 23431, 23447, 23459, 23473, 23497, 23509, 23531, 23537, 23539, 23549,
    23557, 23561, 23563, 23567, 23581, 23593, 23599, 23603, 23609, 23623, 23627,
    23629, 23633, 23663, 23669, 23671, 23677, 23687, 23689, 23719, 23741, 23743,
    23747, 23753, 23761, 23767, 23773, 23789, 23801, 23813, 23819, 23827, 23831,
    23833, 23857, 23869, 23873, 23879, 23887, 23893, 23899, 23909, 23911, 23917,
    23929, 23957, 23971, 23977, 23981, 23993, 24001, 24007, 24019, 24023, 24029,
    24043, 24049, 24061, 24071, 24077, 24083, 24091, 24097, 24103, 24107, 24109,
    24113, 24121, 24133, 24137, 24151, 24169, 24179, 24181, 24197, 24203, 24223,
    24229, 24239, 24247, 24251, 24281, 24317, 24329, 24337, 24359, 24371, 24373,
    24379, 24391, 24407, 24413, 24419, 24421, 24439, 24443, 24469, 24473, 24481,
    24499, 24509, 24517, 24527, 24533, 24547, 24551, 24571, 24593, 24611, 24623,
    24631, 24659, 24671, 24677, 24683, 24691, 24697, 24709, 24733, 24749, 24763,
    24767, 24781, 24793, 24799, 24809, 24821, 24841, 24847, 24851, 24859, 24877,
    24889, 24907, 24917, 24919, 24923, 24943, 24953, 24967, 24971, 24977, 24979,
    24989, 25013, 25031, 25033, 25037, 25057, 25073, 25087, 25097, 25111, 25117,
    25121, 25127, 25147, 25153, 25163, 25169, 25171, 25183, 25189, 25219, 25229,
    25237, 25243, 25247, 25253, 25261, 25301, 25303, 25307, 25309, 25321, 25339,
    25343, 25349, 25357, 25367, 25373, 25391, 25409, 25411, 25423, 25439, 25447,
    25453, 25457, 25463, 25469, 25471, 25523, 25537, 25541, 25561, 25577, 25579,
    25583, 25589, 25601, 25603, 25609, 25621, 25633, 25639, 25643, 25657, 25667,
    25673, 25679, 25693, 25703, 25717, 25733, 25741, 25747, 25759, 25763, 25771,
    25793, 25799, 25801, 25819, 25841, 25847, 25849, 25867, 25873, 25889, 25903,
    25913, 25919, 25931, 25933, 25939, 25943, 25951, 25969, 25981, 25997, 25999,
    26003, 26017, 26021, 26029, 26041, 26053, 26083, 26099, 26107, 26111, 26113,
    26119, 26141, 26153, 26161, 26171, 26177, 26183, 26189, 26203, 26209, 26227,
    26237, 26249, 26251, 26261, 26263, 26267, 26293, 26297, 26309, 26317, 26321,
    26339, 26347, 26357, 26371, 26387, 26393, 26399, 26407, 26417, 26423, 26431,
    26437, 26449, 26459, 26479, 26489, 26497, 26501, 26513, 26539, 26557, 26561,
    26573, 26591, 26597, 26627, 26633, 26641, 26647, 26669, 26681, 26683, 26687,
    26693, 26699, 26701, 26711, 26713, 26717, 26723, 26729, 26731, 26737, 26759,
    26777, 26783, 26801, 26813, 26821, 26833, 26839, 26849, 26861, 26863, 26879,
    26881, 26891, 26893, 26903, 26921, 26927, 26947, 26951, 26953, 26959, 26981,
    26987, 26993, 27011, 27017, 27031, 27043, 27059, 27061, 27067, 27073, 27077,
    27091, 27103, 27107, 27109, 27127, 27143, 27179, 27191, 27197, 27211, 27239,
    27241, 27253, 27259, 27271, 27277, 27281, 27283, 27299, 27329, 27337, 27361,
    27367, 27397, 27407, 27409, 27427, 27431, 27437, 27449, 27457, 27479, 27481,
    27487, 27509, 27527, 27529, 27539, 27541, 27551, 27581, 27583, 27611, 27617,
    27631, 27647, 27653, 27673, 27689, 27691, 27697, 27701, 27733, 27737, 27739,
    27743, 27749, 27751, 27763, 27767, 27773, 27779, 27791, 27793, 27799, 27803,
    27809, 27817, 27823, 27827, 27847, 27851, 27883, 27893, 27901, 27917, 27919,
    27941, 27943, 27947, 27953, 27961, 27967, 27983, 27997, 28001, 28019, 28027,
    28031, 28051, 28057, 28069, 28081, 28087, 28097, 28099, 28109, 28111, 28123,
    28151, 28163, 28181, 28183, 28201, 28211, 28219, 28229, 28277, 28279, 28283,
    28289, 28297, 28307, 28309, 28319, 28349, 28351, 28387, 28393, 28403, 28409,
    28411, 28429, 28433, 28439, 28447, 28463, 28477, 28493, 28499, 28513, 28517,
    28537, 28541, 28547, 28549, 28559, 28571, 28573, 28579, 28591, 28597, 28603,
    28607, 28619, 28621, 28627, 28631, 28643, 28649, 28657, 28661, 28663, 28669,
    28687, 28697, 28703, 28711, 28723, 28729, 28751, 28753, 28759, 28771, 28789,
    28793, 28807, 28813, 28817, 28837, 28843, 28859, 28867, 28871, 28879, 28901,
    28909, 28921, 28927, 28933, 28949, 28961, 28979, 29009, 29017, 29021, 29023,
    29027, 29033, 29059, 29063, 29077, 29101, 29123, 29129, 29131, 29137, 29147,
    29153, 29167, 29173, 29179, 29191, 29201, 29207, 29209, 29221, 29231, 29243,
    29251, 29269, 29287, 29297, 29303, 29311, 29327, 29333, 29339, 29347, 29363,
    29383, 29387, 29389, 29399, 29401, 29411, 29423, 29429, 29437, 29443, 29453,
    29473, 29483, 29501, 29527, 29531, 29537, 29567, 29569, 29573, 29581, 29587,
    29599, 29611, 29629, 29633, 29641, 29663, 29669, 29671, 29683, 29717, 29723,
    29741, 29753, 29759, 29761, 29789, 29803, 29819, 29833, 29837, 29851, 29863,
    29867, 29873, 29879, 29881, 29917, 29921, 29927, 29947, 29959, 29983, 29989,
    30011, 30013, 30029, 30047, 30059, 30071, 30089, 30091, 30097, 30103, 30109,
    30113, 30119, 30133, 30137, 30139, 30161, 30169, 30181, 30187, 30197, 30203,
    30211, 30223, 30241, 30253, 30259, 30269, 30271, 30293, 30307, 30313, 30319,
    30323, 30341, 30347, 30367, 30389, 30391, 30403, 30427, 30431, 30449, 30467,
    30469, 30491, 30493, 30497, 30509, 30517, 30529, 30539, 30553, 30557, 30559,
    30577, 30593, 30631, 30637, 30643, 30649, 30661, 30671, 30677, 30689, 30697,
    30703, 30707, 30713, 30727, 30757, 30763, 30773, 30781, 30803, 30809, 30817,
    30829, 30839, 30841, 30851, 30853, 30859, 30869, 30871, 30881, 30893, 30911,
    30931, 30937, 30941, 30949, 30971, 30977, 30983, 31013, 31019, 31033, 31039,
    31051, 31063, 31069, 31079, 31081, 31091, 31121, 31123, 31139, 31147, 31151,
    31153, 31159, 31177, 31181, 31183, 31189, 31193, 31219, 31223, 31231, 31237,
    31247, 31249, 31253, 31259, 31267, 31271, 31277, 31307, 31319, 31321, 31327,
    31333, 31337, 31357, 31379, 31387, 31391, 31393, 31397, 31469, 31477, 31481,
    31489, 31511, 31513, 31517, 31531, 31541, 31543, 31547, 31567, 31573, 31583,
    31601, 31607, 31627, 31643, 31649, 31657, 31663, 31667, 31687, 31699, 31721,
    31723, 31727, 31729, 31741, 31751, 31769, 31771, 31793, 31799, 31817, 31847,
    31849, 31859, 31873, 31883, 31891, 31907, 31957, 31963, 31973, 31981, 31991,
    32003, 32009, 32027, 32029, 32051, 32057, 32059, 32063, 32069, 32077, 32083,
    32089, 32099, 32117, 32119, 32141, 32143, 32159, 32173, 32183, 32189, 32191,
    32203, 32213, 32233, 32237, 32251, 32257, 32261, 32297, 32299, 32303, 32309,
    32321, 32323, 32327, 32341, 32353, 32359, 32363, 32369, 32371, 32377, 32381,
    32401, 32411, 32413, 32423, 32429, 32441, 32443, 32467, 32479, 32491, 32497,
    32503, 32507, 32531, 32533, 32537, 32561, 32563, 32569, 32573, 32579, 32587,
    32603, 32609, 32611, 32621, 32633, 32647, 32653, 32687, 32693, 32707, 32713,
    32717, 32719, 32749, 32771, 32779, 32783, 32789, 32797, 32801, 32803, 32831,
    32833, 32839, 32843, 32869, 32887, 32909, 32911, 32917, 32933, 32939, 32941,
    32957, 32969, 32971, 32983, 32987, 32993, 32999, 33013, 33023, 33029, 33037,
    33049, 33053, 33071, 33073, 33083, 33091, 33107, 33113, 33119, 33149, 33151,
    33161, 33179, 33181, 33191, 33199, 33203, 33211, 33223, 33247, 33287, 33289,
    33301, 33311, 33317, 33329, 33331, 33343, 33347, 33349, 33353, 33359, 33377,
    33391, 33403, 33409, 33413, 33427, 33457, 33461, 33469, 33479, 33487, 33493,
    33503, 33521, 33529, 33533, 33547, 33563, 33569, 33577, 33581, 33587, 33589,
    33599, 33601, 33613, 33617, 33619, 33623, 33629, 33637, 33641, 33647, 33679,
    33703, 33713, 33721, 33739, 33749, 33751, 33757, 33767, 33769, 33773, 33791,
    33797, 33809, 33811, 33827, 33829, 33851, 33857, 33863, 33871, 33889, 33893,
    33911, 33923, 33931, 33937, 33941, 33961, 33967, 33997, 34019, 34031, 34033,
    34039, 34057, 34061, 34123, 34127, 34129, 34141, 34147, 34157, 34159, 34171,
    34183, 34211, 34213, 34217, 34231, 34253, 34259, 34261, 34267, 34273, 34283,
    34297, 34301, 34303, 34313, 34319, 34327, 34337, 34351, 34361, 34367, 34369,
    34381, 34403, 34421, 34429, 34439, 34457, 34469, 34471, 34483, 34487, 34499,
    34501, 34511, 34513, 34519, 34537, 34543, 34549, 34583, 34589, 34591, 34603,
    34607, 34613, 34631, 34649, 34651, 34667, 34673, 34679, 34687, 34693, 34703,
    34721, 34729, 34739, 34747, 34757, 34759, 34763, 34781, 34807, 34819, 34841,
    34843, 34847, 34849, 34871, 34877, 34883, 34897, 34913, 34919, 34939, 34949,
    34961, 34963, 34981, 35023, 35027, 35051, 35053, 35059, 35069, 35081, 35083,
    35089, 35099, 35107, 35111, 35117, 35129, 35141, 35149, 35153, 35159, 35171,
    35201, 35221, 35227, 35251, 35257, 35267, 35279, 35281, 35291, 35311, 35317,
    35323, 35327, 35339, 35353, 35363, 35381, 35393, 35401, 35407, 35419, 35423,
    35437, 35447, 35449, 35461, 35491, 35507, 35509, 35521, 35527, 35531, 35533,
    35537, 35543, 35569, 35573, 35591, 35593, 35597, 35603, 35617, 35671, 35677,
    35729, 35731, 35747, 35753, 35759, 35771, 35797, 35801, 35803, 35809, 35831,
    35837, 35839, 35851, 35863, 35869, 35879, 35897, 35899, 35911, 35923, 35933,
    35951, 35963, 35969, 35977, 35983, 35993, 35999, 36007, 36011, 36013, 36017,
    36037, 36061, 36067, 36073, 36083, 36097, 36107, 36109, 36131, 36137, 36151,
    36161, 36187, 36191, 36209, 36217, 36229, 36241, 36251, 36263, 36269, 36277,
    36293, 36299, 36307, 36313, 36319, 36341, 36343, 36353, 36373, 36383, 36389,
    36433, 36451, 36457, 36467, 36469, 36473, 36479, 36493, 36497, 36523, 36527,
    36529, 36541, 36551, 36559, 36563, 36571, 36583, 36587, 36599, 36607, 36629,
    36637, 36643, 36653, 36671, 36677, 36683, 36691, 36697, 36709, 36713, 36721,
    36739, 36749, 36761, 36767, 36779, 36781, 36787, 36791, 36793, 36809, 36821,
    36833, 36847, 36857, 36871, 36877, 36887, 36899, 36901, 36913, 36919, 36923,
    36929, 36931, 36943, 36947, 36973, 36979, 36997, 37003, 37013, 37019, 37021,
    37039, 37049, 37057, 37061, 37087, 37097, 37117, 37123, 37139, 37159, 37171,
    37181, 37189, 37199, 37201, 37217, 37223, 37243, 37253, 37273, 37277, 37307,
    37309, 37313, 37321, 37337, 37339, 37357, 37361, 37363, 37369, 37379, 37397,
    37409, 37423, 37441, 37447, 37463, 37483, 37489, 37493, 37501, 37507, 37511,
    37517, 37529, 37537, 37547, 37549, 37561, 37567, 37571, 37573, 37579, 37589,
    37591, 37607, 37619, 37633, 37643, 37649, 37657, 37663, 37691, 37693, 37699,
    37717, 37747, 37781, 37783, 37799, 37811, 37813, 37831, 37847, 37853, 37861,
    37871, 37879, 37889, 37897, 37907, 37951, 37957, 37963, 37967, 37987, 37991,
    37993, 37997, 38011, 38039, 38047, 38053, 38069, 38083, 38113, 38119, 38149,
    38153, 38167, 38177, 38183, 38189, 38197, 38201, 38219, 38231, 38237, 38239,
    38261, 38273, 38281, 38287, 38299, 38303, 38317, 38321, 38327, 38329, 38333,
    38351, 38371, 38377, 38393, 38431, 38447, 38449, 38453, 38459, 38461, 38501,
    38543, 38557, 38561, 38567, 38569, 38593, 38603, 38609, 38611, 38629, 38639,
    38651, 38653, 38669, 38671, 38677, 38693, 38699, 38707, 38711, 38713, 38723,
    38729, 38737, 38747, 38749, 38767, 38783, 38791, 38803, 38821, 38833, 38839,
    38851, 38861, 38867, 38873, 38891, 38903, 38917, 38921, 38923, 38933, 38953,
    38959, 38971, 38977, 38993, 39019, 39023, 39041, 39043, 39047, 39079, 39089,
    39097, 39103, 39107, 39113, 39119, 39133, 39139, 39157, 39161, 39163, 39181,
    39191, 39199, 39209, 39217, 39227, 39229, 39233, 39239, 39241, 39251, 39293,
    39301, 39313, 39317, 39323, 39341, 39343, 39359, 39367, 39371, 39373, 39383,
    39397, 39409, 39419, 39439, 39443, 39451, 39461, 39499, 39503, 39509, 39511,
    39521, 39541, 39551, 39563, 39569, 39581, 39607, 39619, 39623, 39631, 39659,
    39667, 39671, 39679, 39703, 39709, 39719, 39727, 39733, 39749, 39761, 39769,
    39779, 39791, 39799, 39821, 39827, 39829, 39839, 39841, 39847, 39857, 39863,
    39869, 39877, 39883, 39887, 39901, 39929, 39937, 39953, 39971, 39979, 39983,
    39989, 40009, 40013, 40031, 40037, 40039, 40063, 40087, 40093, 40099, 40111,
    40123, 40127, 40129, 40151, 40153, 40163, 40169, 40177, 40189, 40193, 40213,
    40231, 40237, 40241, 40253, 40277, 40283, 40289, 40343, 40351, 40357, 40361,
    40387, 40423, 40427, 40429, 40433, 40459, 40471, 40483, 40487, 40493, 40499,
    40507, 40519, 40529, 40531, 40543, 40559, 40577, 40583, 40591, 40597, 40609,
    40627, 40637, 40639, 40693, 40697, 40699, 40709, 40739, 40751, 40759, 40763,
    40771, 40787, 40801, 40813, 40819, 40823, 40829, 40841, 40847, 40849, 40853,
    40867, 40879, 40883, 40897, 40903, 40927, 40933, 40939, 40949, 40961, 40973,
    40993, 41011, 41017, 41023, 41039, 41047, 41051, 41057, 41077, 41081, 41113,
    41117, 41131, 41141, 41143, 41149, 41161, 41177, 41179, 41183, 41189, 41201,
    41203, 41213, 41221, 41227, 41231, 41233, 41243, 41257, 41263, 41269, 41281,
    41299, 41333, 41341, 41351, 41357, 41381, 41387, 41389, 41399, 41411, 41413,
    41443, 41453, 41467, 41479, 41491, 41507, 41513, 41519, 41521, 41539, 41543,
    41549, 41579, 41593, 41597, 41603, 41609, 41611, 41617, 41621, 41627, 41641,
    41647, 41651, 41659, 41669, 41681, 41687, 41719, 41729, 41737, 41759, 41761,
    41771, 41777, 41801, 41809, 41813, 41843, 41849, 41851, 41863, 41879, 41887,
    41893, 41897, 41903, 41911, 41927, 41941, 41947, 41953, 41957, 41959, 41969,
    41981, 41983, 41999, 42013, 42017, 42019, 42023, 42043, 42061, 42071, 42073,
    42083, 42089, 42101, 42131, 42139, 42157, 42169, 42179, 42181, 42187, 42193,
    42197, 42209, 42221, 42223, 42227, 42239, 42257, 42281, 42283, 42293, 42299,
    42307, 42323, 42331, 42337, 42349, 42359, 42373, 42379, 42391, 42397, 42403,
    42407, 42409, 42433, 42437, 42443, 42451, 42457, 42461, 42463, 42467, 42473,
    42487, 42491, 42499, 42509, 42533, 42557, 42569, 42571, 42577, 42589, 42611,
    42641, 42643, 42649, 42667, 42677, 42683, 42689, 42697, 42701, 42703, 42709,
    42719, 42727, 42737, 42743, 42751, 42767, 42773, 42787, 42793, 42797, 42821,
    42829, 42839, 42841, 42853, 42859, 42863, 42899, 42901, 42923, 42929, 42937,
    42943, 42953, 42961, 42967, 42979, 42989, 43003, 43013, 43019, 43037, 43049,
    43051, 43063, 43067, 43093, 43103, 43117, 43133, 43151, 43159, 43177, 43189,
    43201, 43207, 43223, 43237, 43261, 43271, 43283, 43291, 43313, 43319, 43321,
    43331, 43391, 43397, 43399, 43403, 43411, 43427, 43441, 43451, 43457, 43481,
    43487, 43499, 43517, 43541, 43543, 43573, 43577, 43579, 43591, 43597, 43607,
    43609, 43613, 43627, 43633, 43649, 43651, 43661, 43669, 43691, 43711, 43717,
    43721, 43753, 43759, 43777, 43781, 43783, 43787, 43789, 43793, 43801, 43853,
    43867, 43889, 43891, 43913, 43933, 43943, 43951, 43961, 43963, 43969, 43973,
    43987, 43991, 43997, 44017, 44021, 44027, 44029, 44041, 44053, 44059, 44071,
    44087, 44089, 44101, 44111, 44119, 44123, 44129, 44131, 44159, 44171, 44179,
    44189, 44201, 44203, 44207, 44221, 44249, 44257, 44263, 44267, 44269, 44273,
    44279, 44281, 44293, 44351, 44357, 44371, 44381, 44383, 44389, 44417, 44449,
    44453, 44483, 44491, 44497, 44501, 44507, 44519, 44531, 44533, 44537, 44543,
    44549, 44563, 44579, 44587, 44617, 44621, 44623, 44633, 44641, 44647, 44651,
    44657, 44683, 44687, 44699, 44701, 44711, 44729, 44741, 44753, 44771, 44773,
    44777, 44789, 44797, 44809, 44819, 44839, 44843, 44851, 44867, 44879, 44887,
    44893, 44909, 44917, 44927, 44939, 44953, 44959, 44963, 44971, 44983, 44987,
    45007, 45013, 45053, 45061, 45077, 45083, 45119, 45121, 45127, 45131, 45137,
    45139, 45161, 45179, 45181, 45191, 45197, 45233, 45247, 45259, 45263, 45281,
    45289, 45293, 45307, 45317, 45319, 45329, 45337, 45341, 45343, 45361, 45377,
    45389, 45403, 45413, 45427, 45433, 45439, 45481, 45491, 45497, 45503, 45523,
    45533, 45541, 45553, 45557, 45569, 45587, 45589, 45599, 45613, 45631, 45641,
    45659, 45667, 45673, 45677, 45691, 45697, 45707, 45737, 45751, 45757, 45763,
    45767, 45779, 45817, 45821, 45823, 45827, 45833, 45841, 45853, 45863, 45869,
    45887, 45893, 45943, 45949, 45953, 45959, 45971, 45979, 45989, 46021, 46027,
    46049, 46051, 46061, 46073, 46091, 46093, 46099, 46103, 46133, 46141, 46147,
    46153, 46171, 46181, 46183, 46187, 46199, 46219, 46229, 46237, 46261, 46271,
    46273, 46279, 46301, 46307, 46309, 46327, 46337, 46349, 46351, 46381, 46399,
    46411, 46439, 46441, 46447, 46451, 46457, 46471, 46477, 46489, 46499, 46507,
    46511, 46523, 46549, 46559, 46567, 46573, 46589, 46591, 46601, 46619, 46633,
    46639, 46643, 46649, 46663, 46679, 46681, 46687, 46691, 46703, 46723, 46727,
    46747, 46751, 46757, 46769, 46771, 46807, 46811, 46817, 46819, 46829, 46831,
    46853, 46861, 46867, 46877, 46889, 46901, 46919, 46933, 46957, 46993, 46997,
    47017, 47041, 47051, 47057, 47059, 47087, 47093, 47111, 47119, 47123, 47129,
    47137, 47143, 47147, 47149, 47161, 47189, 47207, 47221, 47237, 47251, 47269,
    47279, 47287, 47293, 47297, 47303, 47309, 47317, 47339, 47351, 47353, 47363,
    47381, 47387, 47389, 47407, 47417, 47419, 47431, 47441, 47459, 47491, 47497,
    47501, 47507, 47513, 47521, 47527, 47533, 47543, 47563, 47569, 47581, 47591,
    47599, 47609, 47623, 47629, 47639, 47653, 47657, 47659, 47681, 47699, 47701,
    47711, 47713, 47717, 47737, 47741, 47743, 47777, 47779, 47791, 47797, 47807,
    47809, 47819, 47837, 47843, 47857, 47869, 47881, 47903, 47911, 47917, 47933,
    47939, 47947, 47951, 47963, 47969, 47977, 47981, 48017, 48023, 48029, 48049,
    48073, 48079, 48091, 48109, 48119, 48121, 48131, 48157, 48163, 48179, 48187,
    48193, 48197, 48221, 48239, 48247, 48259, 48271, 48281, 48299, 48311, 48313,
    48337, 48341, 48353, 48371, 48383, 48397, 48407, 48409, 48413, 48437, 48449,
    48463, 48473, 48479, 48481, 48487, 48491, 48497, 48523, 48527, 48533, 48539,
    48541, 48563, 48571, 48589, 48593, 48611, 48619, 48623, 48647, 48649, 48661,
    48673, 48677, 48679, 48731, 48733, 48751, 48757, 48761, 48767, 48779, 48781,
    48787, 48799, 48809, 48817, 48821, 48823, 48847, 48857, 48859, 48869, 48871,
    48883, 48889, 48907, 48947, 48953, 48973, 48989, 48991, 49003, 49009, 49019,
    49031, 49033, 49037, 49043, 49057, 49069, 49081, 49103, 49109, 49117, 49121,
    49123, 49139, 49157, 49169, 49171, 49177, 49193, 49199, 49201, 49207, 49211,
    49223, 49253, 49261, 49277, 49279, 49297, 49307, 49331, 49333, 49339, 49363,
    49367, 49369, 49391, 49393, 49409, 49411, 49417, 49429, 49433, 49451, 49459,
    49463, 49477, 49481, 49499, 49523, 49529, 49531, 49537, 49547, 49549, 49559,
    49597, 49603, 49613, 49627, 49633, 49639, 49663, 49667, 49669, 49681, 49697,
    49711, 49727, 49739, 49741, 49747, 49757, 49783, 49787, 49789, 49801, 49807,
    49811, 49823, 49831, 49843, 49853, 49871, 49877, 49891, 49919, 49921, 49927,
    49937, 49939, 49943, 49957, 49991, 49993, 49999, 50021, 50023, 50033, 50047,
    50051, 50053, 50069, 50077, 50087, 50093, 50101, 50111, 50119, 50123, 50129,
    50131, 50147, 50153, 50159, 50177, 50207, 50221, 50227, 50231, 50261, 50263,
    50273, 50287, 50291, 50311, 50321, 50329, 50333, 50341, 50359, 50363, 50377,
    50383, 50387, 50411, 50417, 50423, 50441, 50459, 50461, 50497, 50503, 50513,
    50527, 50539, 50543, 50549, 50551, 50581, 50587, 50591, 50593, 50599, 50627,
    50647, 50651, 50671, 50683, 50707, 50723, 50741, 50753, 50767, 50773, 50777,
    50789, 50821, 50833, 50839, 50849, 50857, 50867, 50873, 50891, 50893, 50909,
    50923, 50929, 50951, 50957, 50969, 50971, 50989, 50993, 51001, 51031, 51043,
    51047, 51059, 51061, 51071, 51109, 51131, 51133, 51137, 51151, 51157, 51169,
    51193, 51197, 51199, 51203, 51217, 51229, 51239, 51241, 51257, 51263, 51283,
    51287, 51307, 51329, 51341, 51343, 51347, 51349, 51361, 51383, 51407, 51413,
    51419, 51421, 51427, 51431, 51437, 51439, 51449, 51461, 51473, 51479, 51481,
    51487, 51503, 51511, 51517, 51521, 51539, 51551, 51563, 51577, 51581, 51593,
    51599, 51607, 51613, 51631, 51637, 51647, 51659, 51673, 51679, 51683, 51691,
    51713, 51719, 51721, 51749, 51767, 51769, 51787, 51797, 51803, 51817, 51827,
    51829, 51839, 51853, 51859, 51869, 51871, 51893, 51899, 51907, 51913, 51929,
    51941, 51949, 51971, 51973, 51977, 51991, 52009, 52021, 52027, 52051, 52057,
    52067, 52069, 52081, 52103, 52121, 52127, 52147, 52153, 52163, 52177, 52181,
    52183, 52189, 52201, 52223, 52237, 52249, 52253, 52259, 52267, 52289, 52291,
    52301, 52313, 52321, 52361, 52363, 52369, 52379, 52387, 52391, 52433, 52453,
    52457, 52489, 52501, 52511, 52517, 52529, 52541, 52543, 52553, 52561, 52567,
    52571, 52579, 52583, 52609, 52627, 52631, 52639, 52667, 52673, 52691, 52697,
    52709, 52711, 52721, 52727, 52733, 52747, 52757, 52769, 52783, 52807, 52813,
    52817, 52837, 52859, 52861, 52879, 52883, 52889, 52901, 52903, 52919, 52937,
    52951, 52957, 52963, 52967, 52973, 52981, 52999, 53003, 53017, 53047, 53051,
    53069, 53077, 53087, 53089, 53093, 53101, 53113, 53117, 53129, 53147, 53149,
    53161, 53171, 53173, 53189, 53197, 53201, 53231, 53233, 53239, 53267, 53269,
    53279, 53281, 53299, 53309, 53323, 53327, 53353, 53359, 53377, 53381, 53401,
    53407, 53411, 53419, 53437, 53441, 53453, 53479, 53503, 53507, 53527, 53549,
    53551, 53569, 53591, 53593, 53597, 53609, 53611, 53617, 53623, 53629, 53633,
    53639, 53653, 53657, 53681, 53693, 53699, 53717, 53719, 53731, 53759, 53773,
    53777, 53783, 53791, 53813, 53819, 53831, 53849, 53857, 53861, 53881, 53887,
    53891, 53897, 53899, 53917, 53923, 53927, 53939, 53951, 53959, 53987, 53993,
    54001, 54011, 54013, 54037, 54049, 54059, 54083, 54091, 54101, 54121, 54133,
    54139, 54151, 54163, 54167, 54181, 54193, 54217, 54251, 54269, 54277, 54287,
    54293, 54311, 54319, 54323, 54331, 54347, 54361, 54367, 54371, 54377, 54401,
    54403, 54409, 54413, 54419, 54421, 54437, 54443, 54449, 54469, 54493, 54497,
    54499, 54503, 54517, 54521, 54539, 54541, 54547, 54559, 54563, 54577, 54581,
    54583, 54601, 54617, 54623, 54629, 54631, 54647, 54667, 54673, 54679, 54709,
    54713, 54721, 54727, 54751, 54767, 54773, 54779, 54787, 54799, 54829, 54833,
    54851, 54869, 54877, 54881, 54907, 54917, 54919, 54941, 54949, 54959, 54973,
    54979, 54983, 55001, 55009, 55021, 55049, 55051, 55057, 55061, 55073, 55079,
    55103, 55109, 55117, 55127, 55147, 55163, 55171, 55201, 55207, 55213, 55217,
    55219, 55229, 55243, 55249, 55259, 55291, 55313, 55331, 55333, 55337, 55339,
    55343, 55351, 55373, 55381, 55399, 55411, 55439, 55441, 55457, 55469, 55487,
    55501, 55511, 55529, 55541, 55547, 55579, 55589, 55603, 55609, 55619, 55621,
    55631, 55633, 55639, 55661, 55663, 55667, 55673, 55681, 55691, 55697, 55711,
    55717, 55721, 55733, 55763, 55787, 55793, 55799, 55807, 55813, 55817, 55819,
    55823, 55829, 55837, 55843, 55849, 55871, 55889, 55897, 55901, 55903, 55921,
    55927, 55931, 55933, 55949, 55967, 55987, 55997, 56003, 56009, 56039, 56041,
    56053, 56081, 56087, 56093, 56099, 56101, 56113, 56123, 56131, 56149, 56167,
    56171, 56179, 56197, 56207, 56209, 56237, 56239, 56249, 56263, 56267, 56269,
    56299, 56311, 56333, 56359, 56369, 56377, 56383, 56393, 56401, 56417, 56431,
    56437, 56443, 56453, 56467, 56473, 56477, 56479, 56489, 56501, 56503, 56509,
    56519, 56527, 56531, 56533, 56543, 56569, 56591, 56597, 56599, 56611, 56629,
    56633, 56659, 56663, 56671, 56681, 56687, 56701, 56711, 56713, 56731, 56737,
    56747, 56767, 56773, 56779, 56783, 56807, 56809, 56813, 56821, 56827, 56843,
    56857, 56873, 56891, 56893, 56897, 56909, 56911, 56921, 56923, 56929, 56941,
    56951, 56957, 56963, 56983, 56989, 56993, 56999, 57037, 57041, 57047, 57059,
    57073, 57077, 57089, 57097, 57107, 57119, 57131, 57139, 57143, 57149, 57163,
    57173, 57179, 57191, 57193, 57203, 57221, 57223, 57241, 57251, 57259, 57269,
    57271, 57283, 57287, 57301, 57329, 57331, 57347, 57349, 57367, 57373, 57383,
    57389, 57397, 57413, 57427, 57457, 57467, 57487, 57493, 57503, 57527, 57529,
    57557, 57559, 57571, 57587, 57593, 57601, 57637, 57641, 57649, 57653, 57667,
    57679, 57689, 57697, 57709, 57713, 57719, 57727, 57731, 57737, 57751, 57773,
    57781, 57787, 57791, 57793, 57803, 57809, 57829, 57839, 57847, 57853, 57859,
    57881, 57899, 57901, 57917, 57923, 57943, 57947, 57973, 57977, 57991, 58013,
    58027, 58031, 58043, 58049, 58057, 58061, 58067, 58073, 58099, 58109, 58111,
    58129, 58147, 58151, 58153, 58169, 58171, 58189, 58193, 58199, 58207, 58211,
    58217, 58229, 58231, 58237, 58243, 58271, 58309, 58313, 58321, 58337, 58363,
    58367, 58369, 58379, 58391, 58393, 58403, 58411, 58417, 58427, 58439, 58441,
    58451, 58453, 58477, 58481, 58511, 58537, 58543, 58549, 58567, 58573, 58579,
    58601, 58603, 58613, 58631, 58657, 58661, 58679, 58687, 58693, 58699, 58711,
    58727, 58733, 58741, 58757, 58763, 58771, 58787, 58789, 58831, 58889, 58897,
    58901, 58907, 58909, 58913, 58921, 58937, 58943, 58963, 58967, 58979, 58991,
    58997, 59009, 59011, 59021, 59023, 59029, 59051, 59053, 59063, 59069, 59077,
    59083, 59093, 59107, 59113, 59119, 59123, 59141, 59149, 59159, 59167, 59183,
    59197, 59207, 59209, 59219, 59221, 59233, 59239, 59243, 59263, 59273, 59281,
    59333, 59341, 59351, 59357, 59359, 59369, 59377, 59387, 59393, 59399, 59407,
    59417, 59419, 59441, 59443, 59447, 59453, 59467, 59471, 59473, 59497, 59509,
    59513, 59539, 59557, 59561, 59567, 59581, 59611, 59617, 59621, 59627, 59629,
    59651, 59659, 59663, 59669, 59671, 59693, 59699, 59707, 59723, 59729, 59743,
    59747, 59753, 59771, 59779, 59791, 59797, 59809, 59833, 59863, 59879, 59887,
    59921, 59929, 59951, 59957, 59971, 59981, 59999};
int num_of_element = 6057;
int *arr, n;
typedef struct {
  int first;
  int second;
} pa;
vector<pa> pairs;
void generate(vector<int> numbers) {
  int siz = numbers.size();
  int i;
  if (numbers.size() % 2 != 0) {
    numbers.erase(numbers.begin() + 1);
  }
  for (i = 0; (i + 1) < siz;) {
    arr[numbers[i]] = 1;
    arr[numbers[i + 1]] = 1;
    pa t;
    t.first = numbers[i];
    t.second = numbers[i + 1];
    pairs.push_back(t);
    i = i + 2;
  }
  numbers.clear();
}
void generatePairs() {
  vector<int> numbers;
  for (int pos = 1; pos <= 6056; pos++) {
    int prime = primes[pos];
    if ((2 * prime) > n) return;
    for (int i = 1; (i * prime) <= n; i++) {
      if (arr[i * prime] == 0) numbers.push_back(i * prime);
    }
    generate(numbers);
    numbers.clear();
  }
}
void last() {
  vector<int> numbers;
  for (int i = 2; i <= n; i++) {
    if ((i % 2 == 0) && (arr[i] == 0)) {
      numbers.push_back(i);
    }
  }
  int siz = numbers.size();
  int i;
  for (i = 0; (i + 1) < siz;) {
    arr[numbers[i]] = 1;
    arr[numbers[i + 1]] = 1;
    pa t;
    t.first = numbers[i];
    t.second = numbers[i + 1];
    pairs.push_back(t);
    i = i + 2;
  }
  numbers.clear();
}
int main() {
  scanf("%d", &n);
  arr = (int *)calloc(n + 10, sizeof(int));
  if (n <= 3) {
    printf("0");
    return 0;
  }
  arr = (int *)calloc(n + 10, sizeof(int));
  generatePairs();
  last();
  printf("%d\n", pairs.size());
  int siz = pairs.size();
  for (int i = 0; i < siz; i++) {
    printf("%d %d\n", pairs[i].first, pairs[i].second);
  }
}