def choose(n, a):
    global mod
    x, y = 1, 1
    for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
    return x * pow(y, mod - 2, mod) % mod

n,a,b = map(int,input().split())
mod = pow(10,9)+7
all = pow(2,n,mod)-1
print((all-choose(n,a)-choose(n,b))%mod) def choose(n, a):
    global mod
    x, y = 1, 1
    for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
    return x * pow(y, mod - 2, mod) % mod choose global mod x, y = 1, 1 x 1 y 1 for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
     i range(a) range a x = x * (n - i) % mod x x * (n - i) % mod x * (n - i) x n - i n i mod y = y * (i + 1) % mod y y * (i + 1) % mod y * (i + 1) y i + 1 i 1 mod return x * pow(y, mod - 2, mod) % mod x * pow(y, mod - 2, mod) % mod x * pow(y, mod - 2, mod) x pow(y, mod - 2, mod) pow y mod - 2 mod 2 mod mod n n a a n,a,b = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b mod = pow(10,9)+7 mod pow(10,9)+7 pow(10,9) pow 10 9 7 all = pow(2,n,mod)-1 all pow(2,n,mod)-1 pow(2,n,mod) pow 2 n mod 1 print((all-choose(n,a)-choose(n,b))%mod) print (all-choose(n,a)-choose(n,b))%mod all-choose(n,a)-choose(n,b) all-choose(n,a) all choose(n,a) choose n a choose(n,b) choose n b mod b = map(int,input().split()) map(int,input().split()) b mod = pow(10,9)+7 pow(10,9)+7 mod all = pow(2,n,mod)-1 pow(2,n,mod)-1 all def choose(n, a):
    global mod
    x, y = 1, 1
    for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
    return x * pow(y, mod - 2, mod) % mod def choose(n, a):
    global mod
    x, y = 1, 1
    for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
    return x * pow(y, mod - 2, mod) % mod choose n,a,b = map(int,input().split()) map(int,input().split()) n a,b = map(int,input().split()) map(int,input().split()) a
def choose(n, a):
    global mod
    x, y = 1, 1
    for i in range(a):
        x = x * (n - i) % mod
        y = y * (i + 1) % mod
    return x * pow(y, mod - 2, mod) % mod

n,a,b = map(int,input().split())
mod = pow(10,9)+7
all = pow(2,n,mod)-1
print((all-choose(n,a)-choose(n,b))%mod)