func_code_string: #include <bits/stdc++.h>   using namespace std;   const double eps = 1e-8;   const double pi = acos(-1.0);   int n, m;   bool check(int x) {     int a2 = x / 2, a3 = x / 3, a6 = x / 6;     a2 -= a6;     a3 -= a6;     if (max(n - a2, 0) + max(m - a3, 0) <= a6)       return true;     else       return false;   }   int main() {     cin >> n >> m;     int l = 1, r = 1e7;     int ans = -1;     while (l <= r) {       int mid = (l + r) / 2;       if (check(mid))         r = mid - 1;       else         l = mid + 1;     }     cout << l << endl;     return 0;   }   