Problem:
Score : 100 points

Problem Statement

It is known that the area of a regular dodecagon inscribed in a circle of radius a is 3a^2.

Given an integer r, find the area of a regular dodecagon inscribed in a circle of radius r.

Constraints

1 \leq r \leq 100

r is an integer.

Input

Input is given from Standard Input in the following format:

r

Output

Print an integer representing the area of the regular dodecagon.

Sample Input 1

4

Sample Output 1

48

The area of the regular dodecagon is 3 \times 4^2 = 48.

Sample Input 2

15

Sample Output 2

675

Sample Input 3

80

Sample Output 3

19200

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <algorithm>
#include <bits/stdc++.h>
#include<iostream>
#include<string>
using namespace std;
#define rep(i, n) for (int i = 0; i <(int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
const ll INF = 1<<29;
int main(){
ll n;cin>>n;
vector<ll> a(n);
ll amax=0;
ll bmax=0;
rep(i,n){
    cin>>a[i];
    amax=max(amax,a[i]);
}
rep(i,n){
    if(a[i]==amax)a[i]=0;
    bmax=max(bmax,a[i]);
}
ll cnt=count(all(a),amax);
rep(i,n){
    if(a[i]!=amax)cout<<amax<<endl;
    if(a[i]==amax){
        if(cnt>=2)cout<<amax<<endl;
        if(cnt==1)cout<<bmax<<endl;
    }
}
}