#include using namespace std; typedef long long ll; const int mod = 1e9+7; int t; char c[100]; ll n, k, f[2002002]; ll mpow(ll x, ll n = mod-2, ll m = mod) { ll res = 1; while (n>0) { if (n&1) res = res * x %m; x = x * x %m; n >>= 1; } return res; } ll comb(ll n, ll k) { if (n==-1 && k==0) return 1; if (n