def comb(n, k, mod):

    m = 1
    for i in range(n, n - k, -1):
        m = m * i % mod

    n = 1
    for i in range(1, k + 1):
        n = n * i % mod

    return (m * pow(n, mod - 2, mod) % mod)


def main():

    mod = 1000000007
    n, a, b = map(int, input().split())

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


if __name__ == '__main__':
    main() def comb(n, k, mod):

    m = 1
    for i in range(n, n - k, -1):
        m = m * i % mod

    n = 1
    for i in range(1, k + 1):
        n = n * i % mod

    return (m * pow(n, mod - 2, mod) % mod) comb m = 1 m 1 for i in range(n, n - k, -1):
        m = m * i % mod

     i range(n, n - k, -1) range n n - k n k -1 m = m * i % mod m m * i % mod m * i m i mod n = 1 n 1 for i in range(1, k + 1):
        n = n * i % mod

     i range(1, k + 1) range 1 k + 1 k 1 n = n * i % mod n n * i % mod n * i n i mod return (m * pow(n, mod - 2, mod) % mod) m * pow(n, mod - 2, mod) % mod m * pow(n, mod - 2, mod) m pow(n, mod - 2, mod) pow n mod - 2 mod 2 mod mod n n k k mod mod def main():

    mod = 1000000007
    n, a, b = map(int, input().split())

    ans = pow(2, n, mod) - 1 - comb(n, a, mod) - comb(n, b, mod)
    ans = ans % mod
    print(ans) main mod = 1000000007 mod 1000000007 n, a, b = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b ans = pow(2, n, mod) - 1 - comb(n, a, mod) - comb(n, b, mod) ans pow(2, n, mod) - 1 - comb(n, a, mod) - comb(n, b, mod) pow(2, n, mod) - 1 - comb(n, a, mod) pow(2, n, mod) - 1 pow(2, n, mod) pow 2 n mod 1 comb(n, a, mod) comb n a mod comb(n, b, mod) comb n b mod ans = ans % mod ans ans % mod ans mod print(ans) print ans if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def comb(n, k, mod):

    m = 1
    for i in range(n, n - k, -1):
        m = m * i % mod

    n = 1
    for i in range(1, k + 1):
        n = n * i % mod

    return (m * pow(n, mod - 2, mod) % mod) def comb(n, k, mod):

    m = 1
    for i in range(n, n - k, -1):
        m = m * i % mod

    n = 1
    for i in range(1, k + 1):
        n = n * i % mod

    return (m * pow(n, mod - 2, mod) % mod) comb def main():

    mod = 1000000007
    n, a, b = map(int, input().split())

    ans = pow(2, n, mod) - 1 - comb(n, a, mod) - comb(n, b, mod)
    ans = ans % mod
    print(ans) def main():

    mod = 1000000007
    n, a, b = map(int, input().split())

    ans = pow(2, n, mod) - 1 - comb(n, a, mod) - comb(n, b, mod)
    ans = ans % mod
    print(ans) main
def comb(n, k, mod):

    m = 1
    for i in range(n, n - k, -1):
        m = m * i % mod

    n = 1
    for i in range(1, k + 1):
        n = n * i % mod

    return (m * pow(n, mod - 2, mod) % mod)


def main():

    mod = 1000000007
    n, a, b = map(int, input().split())

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


if __name__ == '__main__':
    main()
