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

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

N = pow(2,n,mod)-1
A = combination(n,a)
B = combination(n,b)
print((N-A-B)%mod)