Akari has n kinds of flowers, one of each kind.

She is going to choose one or more of these flowers to make a bouquet.

However, she hates two numbers a and b, so the number of flowers in the bouquet cannot be a or b.

How many different bouquets are there that Akari can make?

Find the count modulo (10^9 + 7).

Here, two bouquets are considered different when there is a flower that is used in one of the bouquets but not in the other bouquet.

Constraints

* All values in input are integers.
* 2 \leq n \leq 10^9
* 1 \leq a < b \leq \textrm{min}(n, 2 \times 10^5)

Input

Input is given from Standard Input in the following format:


n a b


Output

Print the number of bouquets that Akari can make, modulo (10^9 + 7). (If there are no such bouquets, print `0`.)

Examples

Input

4 1 3


Output

7


Input

1000000000 141421 173205


Output

34076506
// D - Bouquet
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define MOD 1000000007

// a^n mod m を計算する(二分累乗法:O(logn))
ll modpow(ll a, ll n) {
	ll m = MOD;
	ll x = 1;
	while(n){
		if(n & 1) x = x * a % m;
		a = a * a % m;
		n >>= 1;
	}
	return x;
}

// nCr mod m
ll nCr(ll n, ll r){
	ll m = MOD;
	ll a = 1, b = 1;
	for(ll i=1; i<=r; ++i){
		a *= n - i + 1;
		b *= i;
		a %=m;
		b %=m;
	}
	return a * modpow(b, m-2) % m;
}

int main(){
	ll N,A,B; cin>>N>>A>>B;
	ll ans = modpow(2, N) - 1;
	ans -= nCr(N, A);
	ans -= nCr(N, B);
	ans %= MOD;
	if(ans < 0L) ans += MOD;
	cout<< ans <<endl;
}