#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y;
  cin >> n >> m;
  y = 3 * m;
  x = 2 * n;
  for (int i = 6; i <= x && i <= y; i += 6) {
    if (x <= y)
      x += 2;
    else
      y += 3;
  }
  cout << max(x, y);
  return 0;
}
