#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, y, z;
  cin >> x >> y;
  if (x == 1) {
    cout << y;
  } else {
    z = (x * 3) / 2;
    z += y / 2;
    cout << z;
  }
  return 0;
}
