func_code_string: #include <bits/stdc++.h>   using namespace std;   int64_t solve(int m, int n) {     if (m > n) swap(m, n);     if (m == 1) {       if (n <= 3) return 0;       if (n % 6 == 2 || n % 6 == 4) return n - 2;       if (n % 6 == 1 || n % 6 == 5) return n - 1;       if (n % 6 == 3) return n - 3;       return n;     }     if (m == 2) {       if (n <= 2) return 0;       if (n == 3) return 4;       if (n == 4) return 8;       if (n == 7) return 12;       return n * 2;     }     int64_t res = 1LL * m * n;     if (res % 2 == 1) res -= 1;     return res;   }   int main() {     int n, m;     cin >> n >> m;     cout << solve(n, m) << endl;     return 0;   }   