
mod = (10 ** 9 + 7)

def comb(n, r):
    p, q = 1, 1

    for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
    return p * pow(q, mod-2, mod) % mod


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

s = pow(2, n, mod) - 1

print((s - comb(n, a) - comb(n, b)) % mod) mod = (10 ** 9 + 7) mod 10 ** 9 + 7 10 ** 9 10 9 7 def comb(n, r):
    p, q = 1, 1

    for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
    return p * pow(q, mod-2, mod) % mod comb p, q = 1, 1 p 1 q 1 for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
     i range(r) range r p = p *(n-i)%mod p p *(n-i)%mod p *(n-i) p n-i n i mod q = q *(i+1)%mod q q *(i+1)%mod q *(i+1) q i+1 i 1 mod return p * pow(q, mod-2, mod) % mod p * pow(q, mod-2, mod) % mod p * pow(q, mod-2, mod) p pow(q, mod-2, mod) pow q mod-2 mod 2 mod 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 s = pow(2, n, mod) - 1 s pow(2, n, mod) - 1 pow(2, n, mod) pow 2 n mod 1 print((s - comb(n, a) - comb(n, b)) % mod) print (s - comb(n, a) - comb(n, b)) % mod s - comb(n, a) - comb(n, b) s - comb(n, a) s comb(n, a) comb n a comb(n, b) comb n b mod mod = (10 ** 9 + 7) 10 ** 9 + 7 mod b = list(map(int, input().split())) list(map(int, input().split())) b s = pow(2, n, mod) - 1 pow(2, n, mod) - 1 s n, a, b = list(map(int, input().split())) list(map(int, input().split())) n def comb(n, r):
    p, q = 1, 1

    for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
    return p * pow(q, mod-2, mod) % mod def comb(n, r):
    p, q = 1, 1

    for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
    return p * pow(q, mod-2, mod) % mod comb a, b = list(map(int, input().split())) list(map(int, input().split())) a

mod = (10 ** 9 + 7)

def comb(n, r):
    p, q = 1, 1

    for i in range(r):
        p = p *(n-i)%mod
        q = q *(i+1)%mod
    
    return p * pow(q, mod-2, mod) % mod


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

s = pow(2, n, mod) - 1

print((s - comb(n, a) - comb(n, b)) % mod)