Codeforces 546A Soldier and Bananas solution in C++

Codeforces 546A. Soldier and Bananas Question

A. Soldier and Bananas

A soldier wants to buy w bananas in the shop. He has to pay k dollars for the first banana, 2k dollars for the second one and so on (in other words, he has to pay i·k dollars for the i-th banana).

He has n dollars. How many dollars does he have to borrow from his friend soldier to buy w bananas?

Input

The first line contains three positive integers k, n, w (1  ≤  k, w  ≤  1000, 0 ≤ n ≤ 10⁹), the cost of the first banana, initial number of dollars the soldier has and number of bananas he wants.

Output

Output one integer — the amount of dollars that the soldier must borrow from his friend. If he doesn’t have to borrow money, output 0.

Examples

input:

3  17  4

output:

13

Codeforces 546A Soldier and Bananas solution in C++

#include<iostream>
using namespace std;
int main()
{
    int w,k,z;
    long long int n;
    cin>>k>>n>>w;
    int sum=0;
    for(int i=1;i<=w;i++)
    {
        sum=sum+i;
    }
    int m=sum*k;
    int out=m-n;
    if(out<0)
    {
        cout<<"0"<<endl;
    }
    else{   
    cout<<out<<endl;}
}

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