def solve():
    def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

    n,a,b = [int(i) for i in input().split()]
    mod = 10**9 + 7
    ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod)
    print(ans % mod)

if __name__ == "__main__":
    solve() def solve():
    def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

    n,a,b = [int(i) for i in input().split()]
    mod = 10**9 + 7
    ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod)
    print(ans % mod) solve def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

     combis from math import factorial numerator = 1 numerator 1 denominator = 1 denominator 1 for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
         i range(k) range k numerator = numerator * (n-i) % mod numerator numerator * (n-i) % mod numerator * (n-i) numerator n-i n i mod denominator = denominator * (i+1) % mod denominator denominator * (i+1) % mod denominator * (i+1) denominator i+1 i 1 mod return numerator * pow(denominator, mod-2, mod) % mod numerator * pow(denominator, mod-2, mod) % mod numerator * pow(denominator, mod-2, mod) numerator pow(denominator, mod-2, mod) pow denominator mod-2 mod 2 mod mod n n k k mod mod int(i) for i in input().split() for i in input().split() i input().split() ().split () input split for i in input().split() int(i) int i n,a,b = [int(i) for i in input().split()] n [int(i) for i in input().split()] a b mod = 10**9 + 7 mod 10**9 + 7 10**9 10 9 7 ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod) ans pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod) pow(2, n, mod) - 1 - combis(n, a, mod) pow(2, n, mod) - 1 pow(2, n, mod) pow 2 n mod 1 combis(n, a, mod) combis n a mod combis(n, b, mod) combis n b mod print(ans % mod) print ans % mod ans mod if __name__ == "__main__":
    solve() __name__ == "__main__" __name__ "__main__" solve() solve def solve():
    def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

    n,a,b = [int(i) for i in input().split()]
    mod = 10**9 + 7
    ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod)
    print(ans % mod) def solve():
    def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

    n,a,b = [int(i) for i in input().split()]
    mod = 10**9 + 7
    ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod)
    print(ans % mod) solve
def solve():
    def combis(n, k, mod):
        from math import factorial
        numerator = 1
        denominator = 1
        for i in range(k):
            numerator = numerator * (n-i) % mod
            denominator = denominator * (i+1) % mod
        return numerator * pow(denominator, mod-2, mod) % mod

    n,a,b = [int(i) for i in input().split()]
    mod = 10**9 + 7
    ans = pow(2, n, mod) - 1 - combis(n, a, mod) - combis(n, b, mod)
    print(ans % mod)

if __name__ == "__main__":
    solve()