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

def cmb(n,r):
    a,b = 1,1
    for i in range(r):
        a = a * (n-i) % mod
        b = b * (i+1) % mod
    return a * pow(b, mod-2, mod) %mod

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

def cmb(n,r):
    a,b = 1,1
    for i in range(r):
        a = a * (n-i) % mod
        b = b * (i+1) % mod
    return a * pow(b, mod-2, mod) %mod

print((pow(2, n, mod) - cmb(n,a) - cmb(n,b) - 1)%mod)