Problem: PolandBall is a young, clever Ball. He is interested in prime numbers. He has stated a following hypothesis: "There exists such a positive integer n that for each positive integer m number n·m + 1 is a prime number".

Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any n.

Input

The only number in the input is n (1 ≤ n ≤ 1000) — number from the PolandBall's hypothesis. 

Output

Output such m that n·m + 1 is not a prime number. Your answer will be considered correct if you output any suitable m such that 1 ≤ m ≤ 103. It is guaranteed the the answer exists.

Examples

Input

3


Output

1

Input

4


Output

2

Note

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

For the first sample testcase, 3·1 + 1 = 4. We can output 1.

In the second sample testcase, 4·1 + 1 = 5. We cannot output 1 because 5 is prime. However, m = 2 is okay since 4·2 + 1 = 9, which is not a prime number.

Solution (in PYTHON3):

Solution:
n=int(input())
a=[ 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]
if n%2 is 1:
    print(3)
elif n is 2:
    print(4)
else:
    for i in a:
        if n%i!=0:
            break
    x=1
    while(1):
        if (n*x+1)%i is 0:
            print(x)
            break
        x=x+1