# nCr mod m
# rがn/2に近いと非常に重くなる
def combination(n, r, mod=10**9+7):
    n1, r = n+1, min(r, n-r)
    numer = denom = 1
    for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
    return numer * pow(denom, mod-2, mod) % mod

mod = 10**9+7
N, A, B = map(int, input().split())
ans = pow(2, N, mod) - 1 - combination(N, A) - combination(N, B)
ans %= mod
print(ans) def combination(n, r, mod=10**9+7):
    n1, r = n+1, min(r, n-r)
    numer = denom = 1
    for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
    return numer * pow(denom, mod-2, mod) % mod combination n1, r = n+1, min(r, n-r) n1 n+1 n 1 r min(r, n-r) min r n-r n r numer = denom = 1 numer 1 = denom = 1 denom 1 for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
     i range(1, r+1) range 1 r+1 r 1 numer = numer * (n1-i) % mod numer numer * (n1-i) % mod numer * (n1-i) numer n1-i n1 i mod denom = denom * i % mod denom denom * i % mod denom * i denom i mod return numer * pow(denom, mod-2, mod) % mod numer * pow(denom, mod-2, mod) % mod numer * pow(denom, mod-2, mod) numer pow(denom, mod-2, mod) pow denom mod-2 mod 2 mod mod n n r r mod=10**9+7 mod 10**9+7 10**9 10 9 7 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 ans = pow(2, N, mod) - 1 - combination(N, A) - combination(N, B) ans pow(2, N, mod) - 1 - combination(N, A) - combination(N, B) pow(2, N, mod) - 1 - combination(N, A) pow(2, N, mod) - 1 pow(2, N, mod) pow 2 N mod 1 combination(N, A) combination N A combination(N, B) combination N B ans %= mod ans mod print(ans) print ans def combination(n, r, mod=10**9+7):
    n1, r = n+1, min(r, n-r)
    numer = denom = 1
    for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
    return numer * pow(denom, mod-2, mod) % mod def combination(n, r, mod=10**9+7):
    n1, r = n+1, min(r, n-r)
    numer = denom = 1
    for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
    return numer * pow(denom, mod-2, mod) % mod combination B = map(int, input().split()) map(int, input().split()) B N, A, B = map(int, input().split()) map(int, input().split()) N ans = pow(2, N, mod) - 1 - combination(N, A) - combination(N, B) pow(2, N, mod) - 1 - combination(N, A) - combination(N, B) ans mod = 10**9+7 10**9+7 mod A, B = map(int, input().split()) map(int, input().split()) A ans %= mod mod ans
# nCr mod m
# rがn/2に近いと非常に重くなる
def combination(n, r, mod=10**9+7):
    n1, r = n+1, min(r, n-r)
    numer = denom = 1
    for i in range(1, r+1):
        numer = numer * (n1-i) % mod
        denom = denom * i % mod
    return numer * pow(denom, mod-2, mod) % mod

mod = 10**9+7
N, A, B = map(int, input().split())
ans = pow(2, N, mod) - 1 - combination(N, A) - combination(N, B)
ans %= mod
print(ans)
