def main():
    from functools import reduce
    def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

    n, a, b = list(map(int, input().split()))
    mod = 1000000007
    print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod)

if __name__ == '__main__':
    main() def main():
    from functools import reduce
    def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

    n, a, b = list(map(int, input().split()))
    mod = 1000000007
    print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod) main from functools import reduce def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

     a_comb_mod mod = 1000000007 mod 1000000007 r = min(n-r,r) r min(n-r,r) min n-r n r r if r == 0: return 1
         r == 0 r 0 numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1) numer reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1) reduce lambda x, y: x * y % mod x * y % mod x * y x y mod x y range(n, n - r, -1) range n n - r n r -1 1 denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1) denom reduce(lambda x, y: x * y % mod, range(1,r + 1), 1) reduce lambda x, y: x * y % mod x * y % mod x * y x y mod x y range(1,r + 1) range 1 r + 1 r 1 1 denom_inv = pow(denom, mod - 2, mod) denom_inv pow(denom, mod - 2, mod) pow denom mod - 2 mod 2 mod return numer * denom_inv % mod numer * denom_inv % mod numer * denom_inv numer denom_inv mod n n r r n, a, b = list(map(int, input().split())) n list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split a b mod = 1000000007 mod 1000000007 print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod) print (pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b) pow(2, n, mod) - 1 - a_comb_mod(n, a) pow(2, n, mod) - 1 pow(2, n, mod) pow 2 n mod 1 a_comb_mod(n, a) a_comb_mod n a a_comb_mod(n, b) a_comb_mod n b mod if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    from functools import reduce
    def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

    n, a, b = list(map(int, input().split()))
    mod = 1000000007
    print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod) def main():
    from functools import reduce
    def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

    n, a, b = list(map(int, input().split()))
    mod = 1000000007
    print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod) main
def main():
    from functools import reduce
    def a_comb_mod(n, r):
        mod = 1000000007
        r = min(n-r,r)
        if r == 0: return 1
        numer = reduce(lambda x, y: x * y % mod, range(n, n - r, -1), 1)
        denom = reduce(lambda x, y: x * y % mod, range(1,r + 1), 1)
        denom_inv = pow(denom, mod - 2, mod)
        return numer * denom_inv % mod

    n, a, b = list(map(int, input().split()))
    mod = 1000000007
    print((pow(2, n, mod) - 1 - a_comb_mod(n, a) - a_comb_mod(n, b)) % mod)

if __name__ == '__main__':
    main()
