#define _CRT_SECURE_NO_WARNINGS
//Bismillahir-Rahmanir-Rahim (In The Name Of ALLAH)

//everything is long long

//#include<bits/stdc++.h>
//#include<unordered_map>
#include<iostream>
#include<cstdio>
#include<list>
#include<string>
#include<cstring>
#include<sstream>
#include<cctype>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<stack>
#include<fstream>
#include<cstdlib>
#include<vector>
#include<map>
#include<set>
#include<utility>
#include<iomanip>
#include<queue>
#include<deque>
#include<iterator>
#include<assert.h>
#include<bitset>
#include<climits>
#include<ctime>
#include<complex>
using namespace std;

//... Define Section

#define   mem(a,val)		memset(a,val,sizeof(a))
#define   all(a)		    a.begin(),a.end()
#define   sz(A) 		    A.size()
#define   len(A)		    strlen(A)
#define   ff                first
#define   ss                second
#define   pb 			    push_back
#define   PI			    acos(-1.00)
#define   ll			    long long
#define   pii			    pair<ll,ll>
#define   READ 		        freopen("input.txt", "r", stdin)
#define   WRITE 		    freopen("output.txt", "w", stdout)
#define   FOR(i,a,b) 		for(int i=a;i<=b;i++)
#define   RFOR(i,a,b) 		for(int i=a;i>=b;i--)
#define   sfll(a) 		    scanf("%lld",&a)
#define   sfll2(a,b) 		scanf("%lld %lld",&a,&b)
#define   sfll3(a,b,c) 	    scanf("%lld%lld%lld",&a,&b,&c)
#define   cs 			    printf("Case %lld: ",kk++)
#define   cn 			    printf("Case %lld:\n",kk++)
#define   pfll(a) 		    printf("%lld",a)
#define   nl			    printf("\n")
#define   done 		        printf("DONE\n")
#define   EPS			    1e-9
#define   MOD 			    1000000007
#define   MAX			    1e6
#define   fast 		        ios_base::sync_with_stdio(false);

//BitMask Section

#define   checkBit(S, j)    (S & (1 << j))
#define   setBit(S, j)      (S |= (1 << j))
#define   clearBit(S, j)    (S &= ~(1 << j))
#define   toggleBit(S, j)   (S ^= (1 << j))
#define   lowBit(S)         (S & (-S))
#define   setAll(S, n)      (S = (1 << n) - 1)
//Default Function

template<typename T>inline string Tostring(T a){ ostringstream os(""); os << a; return os.str(); } //number to string
template<typename T>inline ll Tolong(T a){ ll res; istringstream os(a); os >> res; return res; } //string to number
template< class T > inline T Bigmod(T n, T m, T mod){ T ans = 1, mult = n%mod; while (m){ if (m & 1) ans = (ans*mult) % mod; m >>= 1; mult = (mult*mult) % mod; }ans %= mod; return ans; }//Big Mod (A^B)%M
template< class T > inline T Modinv(T x, T mod){ return _bigmod(x, (T)mod - 2) % mod; } // Modular Inverse (A/B=A^(-B))%M
template<typename T>inline vector<int> Parse(T str){ vector<int> res; int s; istringstream os(str); while (os >> s)res.pb(s); return res; }//string to vector
template< class T > inline T Lcm(T x, T y){ return x*y / __gcd(x, y); }//LCM (a*b)/gcd(a,b)
template<typename T> inline T pwr(T b, T p) { T res = 1; while (p > 0) { if (p & 1) { res *= b; }b *= b; p >>= 1; }return res; }//power a^b
template <typename T>inline vector< T > Unique(vector< T > v) { sort(v.begin(), v.end()); v.erase(unique(v.begin(), v.end()), v.end()); return v; }// 1 2 1 3 = 1 2 3 (vector)


//Direction Array

//int dx[]={1,0,-1,0};int dy[]={0,1,0,-1}; //4 Direction
//int dx[]={1,1,0,-1,-1,-1,0,1};int dy[]={0,1,1,1,0,-1,-1,-1};//8 direction
//int dx[]={2,1,-1,-2,-2,-1,1,2};int dy[]={1,2,2,1,-1,-2,-2,-1};//Knight Direction

//Running Time

clock_t begn, ed;
double time_spent;
#define   timestart()		begn=clock()
#define   timestop()		ed=clock()
void      timelimit()		{ time_spent = (double)(ed - begn) / CLOCKS_PER_SEC; cerr << "Running Time: " << time_spent << " Seconds" << endl; }
// start coding
vector<string> split(const string& str, const string& delim)
{
	vector<string> tokens;
	size_t prev = 0, pos = 0;
	do
	{
		pos = str.find(delim, prev);
		if (pos == string::npos) pos = str.length();
		string token = str.substr(prev, pos - prev);
		if (!token.empty()) tokens.push_back(token);
		prev = pos + delim.length();
	} while (pos < str.length() && prev < str.length());
	return tokens;
}
int main()
{
	int a,p;
  cin>>a>>p;
  cout<<(a*3+p)/2<<endl;

}


Measured memory_bytes: 256