#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ldb = long double;
using pa = pair<ll, ll>;
using vec = vector<ll>;
const int MOD = 1e9 + 7, INF = INT_MAX, N = 1e5 + 10;
const double PI = acos(-1);
const ll LINF = LLONG_MAX;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ll a, s;
  cin >> a >> s;
  cout << ((a * 3) + s) / 2;
  cerr << "Time taken: " << int((clock() * 1000.) / CLOCKS_PER_SEC) << "ms\n";
  return 0;
}
