//https://codeforces.com/contest/1333/problem/C


//#include <bits/stdc++.h>
 #include <algorithm>
  #include <bitset>
  #include <complex>
  #include <deque>
  #include <exception>
  #include <fstream>
  #include <functional>
  #include <iomanip>
  #include <ios>
  #include <iosfwd>
  #include <iostream>
  #include <istream>
  #include <iterator>
  #include <limits>
  #include <list>
  #include <locale>
  #include <map>
  #include <memory>
  #include <new>
  #include <numeric>
  #include <ostream>
  #include <queue>
  #include <set>
  #include <sstream>
  #include <stack>
  #include <stdexcept>
  #include <streambuf>
  #include <string>
  #include <typeinfo>
  #include <utility>
  #include <valarray>
  #include <vector>
  #include <array>
  #include <atomic>
  #include <chrono>
  #include <condition_variable>
  #include <forward_list>
  #include <future>
  #include <initializer_list>
  #include <mutex>
  #include <random>
  #include <ratio>
  #include <regex>
  #include <scoped_allocator>
  #include <system_error>
  #include <thread>
  #include <tuple>
  #include <typeindex>
  #include <type_traits>
  #include <unordered_map>
  #include <unordered_set>
using namespace std;
#define FOR(i,o,n) for(long long i = o;i<n;i++)
#define oneforall ios::sync_with_stdio(false);cin.tie(0);
#define all(v) (v).begin(),(v).end()
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define int long long 
const long long INF=1e18;
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
typedef vector<int> vi;
typedef vector<long long> vl;
typedef long long ll;
typedef vector<pair<long, long > > vpll;
typedef vector<pair<int, int > > vpii;



int32_t main() {
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	
  ini(x);
  ini(X1);
  out((x*3+x1)/2);
  
	return 0;
}