#!/usr/bin/env python3
def main():
    from math import factorial

    def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

    n, a, b = map(int, input().split())
    mod = 10 ** 9 + 7

    print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod))


if __name__ == '__main__':
    main() def main():
    from math import factorial

    def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

    n, a, b = map(int, input().split())
    mod = 10 ** 9 + 7

    print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod)) main from math import factorial def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

     calc ret = 1 ret 1 for i in range(x):
            ret = ret * (n - i) % mod
         i range(x) range x ret = ret * (n - i) % mod ret ret * (n - i) % mod ret * (n - i) ret n - i n i mod return ret * pow(factorial(x), mod - 2, mod) % mod ret * pow(factorial(x), mod - 2, mod) % mod ret * pow(factorial(x), mod - 2, mod) ret pow(factorial(x), mod - 2, mod) pow factorial(x) factorial x mod - 2 mod 2 mod mod x x n, a, b = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b mod = 10 ** 9 + 7 mod 10 ** 9 + 7 10 ** 9 10 9 7 print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod)) print max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod) max 0 (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1 pow(2, n, mod) - ((calc(a) + calc(b)) % mod) pow(2, n, mod) pow 2 n mod (calc(a) + calc(b)) % mod calc(a) + calc(b) calc(a) calc a calc(b) calc b mod 1 mod if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    from math import factorial

    def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

    n, a, b = map(int, input().split())
    mod = 10 ** 9 + 7

    print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod)) def main():
    from math import factorial

    def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

    n, a, b = map(int, input().split())
    mod = 10 ** 9 + 7

    print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod)) main
#!/usr/bin/env python3
def main():
    from math import factorial

    def calc(x):
        ret = 1
        for i in range(x):
            ret = ret * (n - i) % mod
        return ret * pow(factorial(x), mod - 2, mod) % mod

    n, a, b = map(int, input().split())
    mod = 10 ** 9 + 7

    print(max(0, (pow(2, n, mod) - ((calc(a) + calc(b)) % mod) - 1) % mod))


if __name__ == '__main__':
    main()
