#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef vector<int> V;
const long long MOD=1000000007LL;
const long long INFL=1LL << 60;
const int INF=1<<29;


int main() {
    int a,p;
    cin >>A>>P;
    cout<<(3*A+P)/2<<endl;
    return 0;
}