#include<bits/stdc++.h>
using namespace std;
//#include<atcoder/all>
//using mint = atcoder::modint998244353;
#define int long long
vector<int> kai,inv;
int mod = 1000000007;
int f(int n, int k) {
  return kai[n]*inv[k]%mod*inv[n-k]%mod;
}
int INV(int x) {
  int e = mod-2;
  bitset<30> b(e);
  int p = x, ans = 1;
  while(e > 0) {
    if(e%2 == 1) ans*=p,ans%=mod;
    e/=2;
    p*=p;
    p%=mod;
  }
  return ans;
}
void TLE() {
  for(int i = 0; i < 998244353; i++) cout << "TLE" << endl;
}
signed main() {
  int T;
  cin >> T;
  cin >> T;
  kai.resize(200001);
  inv.resize(200001);
  kai[0] = 1, inv[0] = 1;
  for(int i = 1; i <= 200000; i++) kai[i] = kai[i-1]*i%mod, inv[i] = inv[i-1]*INV(i)%mod;
  while(T--) {
    double N,M;
    cin >> N >> M;
    int n = N, m = M;
    if(T > 0) {
      if(n != N || m != M) cout << 0 << endl;
      else cout << f(m,n) << endl;
    }
    else cout << -1 << endl;
  }
}