#include <bits/stdc++.h>
int main(int argc, const char* argv[]) {
  std::ifstream in("input.txt");
  std::cin.rdbuf(in.rdbuf());
  int A, P;
  std::cin >> A >> P;
  std::cout << (A * 3 + P) / 2 << std::endl;
  return 0;
}
