Problem:
Score : 100 points

Problem Statement

We have A apples and P pieces of apple.

We can cut an apple into three pieces of apple, and make one apple pie by simmering two pieces of apple in a pan.

Find the maximum number of apple pies we can make with what we have now.

Constraints

All values in input are integers.

0 \leq A, P \leq 100

Input

Input is given from Standard Input in the following format:

A P

Output

Print the maximum number of apple pies we can make with what we have.

Sample Input 1

1 3

Sample Output 1

3

We can first make one apple pie by simmering two of the three pieces of apple. Then, we can make two more by simmering the remaining piece and three more pieces obtained by cutting the whole apple.

Sample Input 2

0 1

Sample Output 2

0

We cannot make an apple pie in this case, unfortunately.

Sample Input 3

32 21

Sample Output 3

58

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

#include<bits/stdc++.h>

using namespace std;
using   ll=long long;

#define fast        	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

#define endl        	"\n"
#define pb          	push_back
#define mp          	make_pair
#define F           	first
#define S           	second
#define int             long long int
#define pll				pair<int , int>

#define ALL(v)      	v.begin(),v.end()
#define ALLR(v)     	v.rbegin(),v.rend()
#define pii         	3.14159265358979323
#define inf     		LLONG_MAX
#define ones(x)     	__builtin_popcount(x)
#define fill(a,b)   	memset(a,b,sizeof(a))
#define mod 			1000000007
#define hell            998244353 

ll mod_pow(ll a,ll b,ll m) 
{
    ll res = 1;
    while(b)	
    {
        if(b&1) 	
        {
        	res=(res*a) % m;
        }
        a=(a*a) % m;
        b>>=1;
    }
    return res;
}

ll mod_inverse(ll a) 
{
	return mod_pow(a , mod-2 , mod);
}

void solve() 
{
	int a , b;
	
	cin >> a >> b;
	
	cout << (3*a + b)/2;
}

signed main() {
    fast;
    
    int t = 1;
    
	//cin >> t;
    
    while(t--) {
        solve();
    }
 
    return 0;
}