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