from functools import reduce
MOD = 10**9 + 7
n, a, b = map(int, input().split())

def comb(n, k):
    def mul(a, b):
        return a*b%MOD
    x = reduce(mul, range(n, n-k, -1))
    y = reduce(mul, range(1, k+1))
    return x*pow(y, MOD-2, MOD) % MOD

ans = (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD

print(ans) from functools import reduce MOD = 10**9 + 7 MOD 10**9 + 7 10**9 10 9 7 n, a, b = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b def comb(n, k):
    def mul(a, b):
        return a*b%MOD
    x = reduce(mul, range(n, n-k, -1))
    y = reduce(mul, range(1, k+1))
    return x*pow(y, MOD-2, MOD) % MOD comb def mul(a, b):
        return a*b%MOD
     mul return a*b%MOD a*b%MOD a*b a b MOD a a b b x = reduce(mul, range(n, n-k, -1)) x reduce(mul, range(n, n-k, -1)) reduce mul range(n, n-k, -1) range n n-k n k -1 y = reduce(mul, range(1, k+1)) y reduce(mul, range(1, k+1)) reduce mul range(1, k+1) range 1 k+1 k 1 return x*pow(y, MOD-2, MOD) % MOD x*pow(y, MOD-2, MOD) % MOD x*pow(y, MOD-2, MOD) x pow(y, MOD-2, MOD) pow y MOD-2 MOD 2 MOD MOD n n k k ans = (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD ans (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD pow(2, n, MOD)-1-comb(n,a)-comb(n,b) pow(2, n, MOD)-1-comb(n,a) pow(2, n, MOD)-1 pow(2, n, MOD) pow 2 n MOD 1 comb(n,a) comb n a comb(n,b) comb n b MOD print(ans) print ans n, a, b = map(int, input().split()) map(int, input().split()) n MOD = 10**9 + 7 10**9 + 7 MOD b = map(int, input().split()) map(int, input().split()) b def comb(n, k):
    def mul(a, b):
        return a*b%MOD
    x = reduce(mul, range(n, n-k, -1))
    y = reduce(mul, range(1, k+1))
    return x*pow(y, MOD-2, MOD) % MOD def comb(n, k):
    def mul(a, b):
        return a*b%MOD
    x = reduce(mul, range(n, n-k, -1))
    y = reduce(mul, range(1, k+1))
    return x*pow(y, MOD-2, MOD) % MOD comb a, b = map(int, input().split()) map(int, input().split()) a ans = (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD ans
from functools import reduce
MOD = 10**9 + 7
n, a, b = map(int, input().split())

def comb(n, k):
    def mul(a, b):
        return a*b%MOD
    x = reduce(mul, range(n, n-k, -1))
    y = reduce(mul, range(1, k+1))
    return x*pow(y, MOD-2, MOD) % MOD

ans = (pow(2, n, MOD)-1-comb(n,a)-comb(n,b)) % MOD

print(ans)