#include <bits/stdc++.h>
using namespace std;
const int N = (int)(1e6) + 322;
const long long INF = 2e18 + 17;
const int inf = 2e9;
const int mod = 1000000007;
const double eps = 1e-9;
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int nbr_bits(int a) { return log2(a) + 1; }
int binpow(int a, int n, int mod) {
  int res = 1;
  while (n) {
    if (n & 1) {
      res *= a;
      res %= mod;
    }
    a *= a;
    a %= mod;
    n >>= 1;
  }
  return res;
}
int fastpow(int a, int n, int mod) {
  if (n == 0) return 1;
  if (n % 2 == 0) {
    int res = fastpow(a, n / 2, mod);
    res *= res;
    res %= mod;
    return res;
  }
  int res = (fastpow(a, n - 1, mod) * a) % mod;
  return res;
}
signed main() {
  int n, k;
  cin >> n >> k;
  int sum = n * 3 + k;
  cout << sum / 2 << endl;
  return 0;
}
