func_code_string: #include <bits/stdc++.h>   using namespace std;   const long ka[6] = {0, 0, 0, 0, 2, 4};   int main() {     long long n, m;     while (cin >> n >> m) {       if (n > m) {         int tmp = n;         n = m;         m = tmp;       }       long long ret;       if (n == 1)         ret = m / 6 * 6 + ka[m % 6];       else if (n == 2) {         if (m == 2)           ret = 0;         else if (m == 3)           ret = 4;         else if (m == 7)           ret = 12;         else           ret = n * m;       } else {         if (n % 2 && m % 2)           ret = n * m - 1;         else           ret = n * m;       }       cout << ret << endl;     }     return 0;   }   