Odd one Out

 Problem:-

Alice and Bob are getting bored so they decided to play a game.

Alice has n cards having the first n odd numbers written on them. He removes one of the cards at random and hands the remaining n-1 cards to Bob. Help Bob to find the value of the card Alice has removed.

Input

The first line contains n the numbers of cards Alice has.

The second line contains n-1 space-separated integers representing the values of cards that Bob got.

Output

Print the value of card Alice removed.

Constraints

$1\le n\le 4000000$

 

Sample Input

5
3 1 9 5

Sample Output

7

Time Limit: 1

Memory Limit: 512

Source Limit:

Explanation

The first 5 odd numbers are 1, 3, 5, 7 and 9 out of which 7 is missing.

Code (c++):-

#include<iostream>

using namespace std;

int main()

{

    // these three lines only for decrease the time

    ios_base::sync_with_stdio(false);

    cin.tie(0);

    cout.tie(0);

    long long n,sum=0,a;

    cin>>n;

    for(long long i=0;i<n-1;i++)

    {

        cin>>a;

        sum=sum+a;

    }

    cout<<n*n-sum;

    return 0;

}

Code (c):-

#include <stdio.h>

int main(){

long n,d;

scanf("%ld", &n);

long tot=n*n,sum=0;

for (int i=0;i<n-1;i++)

{

scanf("%ld",&d);

sum+=d;

}

printf("%ld\n",tot - sum);

}