#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include //#include #pragma warning(disable:4996) typedef long long ll; typedef unsigned long long ull; #define MIN(a, b) ((a)>(b)? (b): (a)) #define MAX(a, b) ((a)<(b)? (b): (a)) #define LINF 9223300000000000000 #define LINF2 1223300000000000000 #define INF 2140000000 const long long MOD = 1000000007; //const long long MOD = 998244353; using namespace std; const int max_comb=210000; vector fac(max_comb+1); //n! (mod M) vector ifac(max_comb+1); //k!^(-1) (mod M) ll mpow(ll x, ll n){ //x^n(mod M) ll ans = 1; while(n != 0){ if(n&1) ans = ans*x % MOD; x = x*x % MOD; n = n >> 1; } return ans; } ll minv(ll x){ return mpow( x, MOD-2 ); } ll comb(int a, int b){ // C(a,b) = a! * b!^(-1) * (a-b)^(-1) if(a == 0 && b == 0)return 1; if(a < b || a < 0)return 0; ll tmp = ifac[a-b]* ifac[b] % MOD; return tmp * fac[a] % MOD; } ll perm(int a, int b){ // P(a,b) = a! * (a-b)!^(-1) if(b == 0)return 1; if(a < b || a < 0)return 0; ll tmp = ifac[a-b] % MOD; return tmp * fac[a] % MOD; } void pre_comb() { fac[0] = 1; ifac[0] = 1; for(int i = 0; i= K) { ll tmp0 = calc(n, i); ll tmp1 = calc(m, i); ll ans0 = tmp0 * tmp1 % MOD; ans0 = ans0 * minv(i) % MOD; ans = (ans + ans0) % MOD; } } printf("%lld\n", ans); return; } int main(int argc, char* argv[]) { #if 1 solve(); #else int T; scanf("%d", &T); int t; for(t=0; t