func_code_string: #include <bits/stdc++.h>   using namespace std;   unsigned long long const Mod = 1000000007;   unsigned long long sq_sum(unsigned long long n) {     unsigned long long ret = n;     ret = (n * (n + 1));     ret /= 2;     if (ret % 3 == 0) {       return ((ret / 3) % Mod * (2 * n + 1)) % Mod;     } else {       return ((ret % Mod) * ((2 * n + 1) / 3)) % Mod;     }   }   unsigned long long check(unsigned long long a, unsigned long long b) {     unsigned long long ret = 0;     for (unsigned long long x = b; x < 100000; ++x) {       if (x % b != 0) {         unsigned long long t1 = x / b;         unsigned long long t2 = x % b;         if (t1 % t2 == 0 && t1 / t2 <= a) ret += x;       }     }     return ret;   }   int main() {     unsigned long long a, b;     while (cin >> a >> b) {       cout << (((a * (a + 1) / 2) % Mod * b + a) % Mod *                ((b * (b - 1) / 2) % Mod)) %                   Mod            << endl;     }   }   