/*** author: yuji9511 ***/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using lpair = pair<ll, ll>;
const ll MOD = 1e9+7;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i=(m);i<(n);i++)
#define rrep(i,m,n) for(ll i=(m);i>=(n);i--)
#define printa(x,n) for(ll i=0;i<n;i++){cout<<(x[i])<<" \n"[i==n-1];};
void print() {}
template <class H,class... T>
void print(H&& h, T&&... t){cout<<h<<" \n"[sizeof...(t)==0];print(forward<T>(t)...);}

ll arr[] = {641102369, 104818485, 60310577, 122646464, 807196544, 327677062, 653842498, 274708032, 709905123, 75821910, 5775243, 726541565, 630044193, 930509622, 537185615, 518384518, 860692604, 29182656, 252663411, 489189987, 227118432, 203593743, 488159830, 170423918, 436447911, 720765503, 251142165, 527712549, 730470275, 969446696, 427440033, 626629257, 350719072, 201159489, 48412268, 50566898, 448285557, 364553199, 264446031, 553783404, 66211768, 961388180, 479274092, 728614729, 370483249, 202228258, 473769029, 194780386, 439485849, 102003465, 824584785, 379467832, 707266385, 215074126, 923941194, 330696450, 456450724, 397674762, 993357299, 487845132, 181582824, 685679903, 683174440, 657269682, 585830429, 458948225, 682657082, 586370736, 331132622, 703390292, 193265703, 634718619, 303428241, 965483921, 31429587, 636936598, 204094367, 248363375, 255514638, 47886326, 414876793, 685431602, 271612229, 164069309, 309284573, 578095544, 884350578, 548390096, 192744422, 707381332, 762604198, 595933670, 881428239, 367468849, 419203080, 533573004, 915035094, 561745251, 675087136, 252318119, 62492226, 62050918, 988741396, 875341739, 899580587, 909930436, 104925393, 830337749, 830508025, 664540443, 756536673, 534388045, 990119502, 101825720, 23526281, 987088767, 669403920, 447489451, 202249825, 661968935, 128816817, 344224914, 328642463, 175602622, 831463898, 952440234, 434569429, 903871785, 314620445, 393166667, 123766919, 676509435, 62794640, 467967150, 262136573, 832084370, 127763685, 966636051, 813768418, 273353405, 388618416, 105484757, 784885691, 310722997, 215720378, 118666381, 48242578, 847749190, 108513056, 548153492, 696528086, 704359245, 838747065, 32443183, 40297561, 261804864, 347105656, 995838608, 219216038, 213962841, 313657455, 266980500, 490520669, 402732505, 502746055, 608863025, 730294926, 51272133, 190867484, 599065709, 319518353, 227723665, 418002812, 760838369, 850175829, 758896788, 499498510, 811549798, 166321920, 55153481, 276850936, 458120983, 644607065, 544763458, 549415797, 904317761, 399456997, 657985949, 527272502, 936282234, 193558584, 594702196, 103622382, 696456732, 359624968, 775278212, 623134717, 500218517, 134185629, 550706249, 862847328, 479938938, 404593470, 226045897, 208473286, 497957511, 409229480, 277122390, 857468429, 902357348, 544749215, 617440395, 507967368, 438047543, 122307665, 849046130, 882477834, 597600022, 173441108, 383383668, 353373516, 801138078, 584709489, 983230922, 738720032, 984519118, 540657760, 368724401, 890303371, 538102279, 197601278, 138155479, 359807733, 107786814, 281136304, 245495966, 1119038, 320330946, 65585583, 815452441, 907465546, 343681379, 13341748, 919564991, 38400258, 240949488, 18881330, 334074278, 341236370, 455967731, 873937152, 53020195, 786073704, 48502274, 91883831, 973954116, 109960658, 432293678, 12000048, 881675217, 276896038, 763887446, 758326125, 398998297, 376698569, 248109230, 791543657, 360860800, 409081264, 841784400, 291020299, 809147679, 158673019, 399553564, 119254695, 162995877, 126090914, 334614795, 943535859, 586719444, 57814722, 917194701, 30820858, 177088733, 246270277, 239734166, 998785395, 377095983, 799837151, 821805075, 953553302, 640575850, 425682694, 18238092, 911086490, 380992670, 676596046, 2266902, 658038077, 916643472, 991837453, 373382608, 422658290, 306827191, 411596172, 518895979, 485985272, 236414387, 984628170, 204487456, 873026820, 223232071, 181094913, 22864344, 201374440, 687290993, 825942875, 805978575, 504929588, 165761878, 501107609, 130812423, 389736380, 585477275, 975829496, 607197088, 902259846, 454174486, 1612152, 102482787, 814174465, 472915080, 93176974, 147122795, 918054404, 544120040, 359472232, 462635603, 278367526, 423225265, 111527295, 440109961, 774578943, 460191780, 130297137, 587630590, 156573473, 954637481, 959499253, 155520960, 92804723, 372623568, 167090766, 833586664, 575203708, 123842088, 819210605, 130442609, 269188308, 606512295, 261496256, 7868360, 944144166, 857938291, 669394030, 320392760, 295822167, 896266185, 491707787, 75610797, 156365526, 530455485, 945481234, 675738703, 616958962, 480154975, 498706795, 351628023, 38179488, 37991289, 161778213, 619852221, 249688878, 906438791, 979446018, 472201158, 934687579, 400960194, 311936783, 315358553, 735807693, 781870154, 731887086, 944949679, 713755616, 522576965, 191414967, 769581288, 133088116, 266758019, 594121619, 710286802, 450388816, 405131594, 791556256, 697093401, 784156746, 489190745, 688163551, 409319440, 911265548, 826999759, 436426022, 765776738, 449309738, 540574170, 697914009, 106315823, 374480497, 854277988, 806651068, 317234250, 845896803, 704503786, 456670732, 883183327, 192904270, 635721339, 421894439, 35435194, 643036510, 754090629, 832271076, 60873518, 102168071, 800649755, 968060300, 234954516, 585412309, 172764421, 188188293, 777732208, 344510637, 641415354, 932032601, 57032574, 167534360, 813123453, 161377338, 999575938, 150119439, 386696154, 929968335, 382084101, 8024543, 662177405, 167714515, 761630159, 637480359, 393208384, 964710913, 293376282, 679121742, 615338602, 460957073, 868333310, 374842794, 371841544, 323684501, 261025976, 953841945, 921457530, 854388099, 206419459, 577458636, 229998249, 676259541, 784201491, 638639073, 100455569, 311626114, 890189839, 919279257, 504426116, 357612254, 655201159, 195380280, 628859494, 796989937, 583570104, 813102064, 529775540, 179683249, 760619913, 637906638, 230455528, 852446295, 960424445, 532749147, 673062691, 193323681, 950917141, 470857434, 600694926, 197716069, 790383488, 528964477, 611072079, 406988688, 865822376, 516744099, 397992771, 222465443, 215415079, 233955811, 772702914, 121569571, 71793603, 781757290, 859212960, 216025726, 872871507, 205816054, 147016127, 950900430, 467524114, 89938823, 952158665, 647554067, 285561813, 90827232, 223202808, 578796645, 615274402, 138589945, 221718024, 292842151, 986865455, 896620331, 563693849, 833443259, 335558214, 86110950, 138213658, 308120313, 577433386, 797167504, 629624516, 28040941, 280196735, 131944701, 330114986, 994277835, 182022448, 132200890, 178209882, 582104355, 96125953, 38129642, 312664495, 703571519, 366702332, 258456725, 339212053, 158095, 313985352, 879397962, 757222089, 881746671, 245062883, 926668488, 165440441, 485535416, 883191807, 457311094, 269867015, 968853662, 76587003, 917996265, 398871229, 466055214, 181043323, 47479057, 836006686, 490332325, 909308257, 29384812, 802362338, 930579035, 20739347, 95442303, 657757403, 737779990, 494941834, 356992466, 716722152, 388397959, 743882906, 858605478, 147670945, 636839245, 927388317, 430810230, 818840022, 420607628, 552793978, 666661132, 946543214, 554388678, 530461425, 13370869, 65201003, 936481192, 272325994, 408612055, 947668039, 27463622, 698386535, 509945856, 509790590, 917560505, 816184330, 441126736, 766081415, 390259792, 156058183, 240036157, 745371572, 52122183, 865945508, 608621778, 850373792, 663928266, 550892371, 594123578, 716403935, 823772331, 170895407, 138994430, 523884128, 313089166, 171479257, 924901994, 268773411, 599702269, 542804573, 696487881, 2105831, 329224028, 853926583, 97892915, 567215694, 659954825, 703774286, 885114206, 536542848, 925893252, 111805458, 241234751, 480795159, 664237630, 527057841, 897100065, 314199964, 469914899, 258130576, 420902388, 995112496, 777318419, 533194448, 851116611, 848300059, 944316155, 223993486, 626565799, 628221961, 106579490, 205813046, 375027952, 923972754, 773963555, 396701156, 105142082, 671226838, 443000539, 668426078, 861043529, 8845567, 978942509, 486064573, 488727276, 600590523, 222836701, 273253219, 91630181, 576113180, 546068535, 561540343, 10792263, 943129802, 351852968, 625767785, 467817644, 8961550, 915858343, 779290566, 183712724, 389209872, 702042064, 618417640, 146232789, 531324214, 90142871, 488269438, 898956907, 967672978, 6167328, 74937261, 642748577, 198972579, 434943648, 273082934, 175251291, 367586504, 928560804, 519172322, 149410649, 994335870, 353804154, 104800536, 770837182, 51374755, 584996003, 552080414, 760085013, 441756787, 516463285, 25437845, 189938975, 788939190, 871699156, 310099367, 610363086, 844405909, 633788902, 542030758, 303181396, 147871553, 392280622, 375462363, 727439580, 282215826, 594449778, 784170433, 145360170, 673629519, 41069414, 110042976, 922217639, 871131007, 74678740, 303601639, 833911127, 226443744, 826899855, 1761469, 786816607, 967035458, 488943604, 944037047, 547505448, 902469434, 588811146, 366691415, 268999120, 207730317, 119431084, 808903304, 717076911, 488948136, 394246697, 614204148, 327586942, 865129939, 306196318, 939406463, 193627409, 767323645, 177184823, 861924358, 816523957, 869099701, 596155286, 116414979, 783469234, 87130396, 578657172, 769966342, 585482568, 16594075, 874648848, 492097673, 938631856, 880107963, 103872946, 388006632, 545900968, 905991566, 418163874, 178145608, 701644626, 690535907, 608386958, 341611310, 155505310, 510196827, 477430250, 237674265, 966795515, 670794013, 738409801, 583629963, 748485548, 151264760, 678180842, 519795158, 920112162, 300138558, 150235335, 146881481, 507052184, 951494765, 250344444, 387447657, 248322546, 463069437, 314980176, 669754074, 229163405, 476666756, 815334097, 707168528, 380654482, 58252413, 182323488, 470643987, 970826613, 234233704, 829459147, 666582533, 110940874, 104407598, 982460481, 274445598, 7024370, 862831377, 833221694, 330372656, 781208006, 708026397, 122874372, 350324799, 116636693, 331996093, 482042137, 917742943, 498352564, 74632571, 295841940, 925405821, 545551486, 84834837, 390506676, 808158497, 621817024, 422659656, 920015671, 330795277, 434229583, 651801661, 818633715, 358902223, 525553449, 376747803, 96019813, 251735186, 535724610, 693007388, 735427287, 688986423, 122999578, 157079586, 494403293, 185157417, 948168371, 724746006, 351302120, 962227972, 325372676, 786913848, 103492735, 410650078, 524679866, 275672338, 214845924, 892604671, 633552411, 756726188, 610166554, 146454940, 107743646, 269236963, 754541178, 810235139, 986276099, 734104915, 608296472, 775810797, 822995365, 733789616, 771865665, 418405015, 359994989, 377915097, 229855164, 224411867, 462111521, 862338476, 900441068, 694346016, 768798462, 517652691, 168217611, 266820154, 473146834, 476074482, 552182233, 949313880, 871690478, 301063741, 164172460, 438405853, 325496407, 814037185, 967576926, 573323548, 882385603, 406088123, 410401233, 684062376, 657732213, 361533587, 48385277, 125876811, 312330178, 976635451, 395046936, 391625835, 189136406, 953226339, 226454389, 366744284, 683865613, 717176808, 322111006, 214918103, 59829549, 764616449, 55714423, 983319618, 158186251, 212543325, 944741043, 905206729, 591973192, 829383948, 638364042, 458918733, 323895625, 138472286, 493435549, 996433701, 301288732, 515415310, 97031835, 68735384, 377451664, 212120317, 199349197, 187046634, 265414352, 282808100, 229822519, 434952461, 601094801, 237157677, 56597548, 786308426, 650703482, 740087892};

struct BigCombination{
private:
    ll N;

public:
    BigCombination(ll n){
        N = n;
    }
    ll power(ll x, ll n){
        if(n == 0) return 1LL;
        ll res = power(x * x % MOD, n/2);
        if(n % 2 == 1) res = res * x % MOD;
        return res;
    }
    ll fac(ll n){
        ll v = 1;
        ll res = 1;
        ll cnt = 0;
        ll tt = 1000000;
        for(ll i = 1; (i+tt) <= n; i += tt){
            res *= arr[cnt];
            res %= MOD;
            v = i+tt;
            cnt++;
        }
        rep(i,v,n+1){
            res *= i;
            res %= MOD;
        }
        return res;
    }

    ll facinv(ll n){
        return power(fac(n), MOD-2);
    }

    ll nck(ll n, ll k){
        if(k == 0 || n == k) return 1LL;
        return fac(n) * facinv(k) % MOD * facinv(n-k) % MOD;      
    }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll N,A,B;
    cin >> N >> A >> B;
    BigCombination cb(200010);
    ll ans = (cb.power(2, N) - 1 + MOD) % MOD;
    ans = (ans - cb.nck(N, A) - cb.nck(N, B) + 2 * MOD) % MOD;
    print(ans);
}


Measured memory_bytes: 256