Problem:
Score : 100 points

Problem Statement

You went shopping to buy cakes and donuts with X yen (the currency of Japan).

First, you bought one cake for A yen at a cake shop.
Then, you bought as many donuts as possible for B yen each, at a donut shop.

How much do you have left after shopping?

Constraints

1 \leq A, B \leq 1 000

A + B \leq X \leq 10 000

X, A and B are integers.

Input

Input is given from Standard Input in the following format:

X
A
B

Output

Print the amount you have left after shopping.

Sample Input 1

1234
150
100

Sample Output 1

84

You have 1234 - 150 = 1084 yen left after buying a cake.
With this amount, you can buy 10 donuts, after which you have 84 yen left.

Sample Input 2

1000
108
108

Sample Output 2

28

Sample Input 3

579
123
456

Sample Output 3

0

Sample Input 4

7477
549
593

Sample Output 4

405

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

#include <iostream>
#include <vector>
#include <unordered_map>
#include <map>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <deque>
#include <cmath>
#include <stack>
#include <queue>
#include <string>
#include <locale>
#include <iomanip>

#define nl '\n';

using namespace std;

int x, a, b;

int main(){

    cin >> x >> a >> b;

    x = x - a;

    cout << x%b;


}

//g++ -std=c++14 comp.cpp -o b; ./b.exe
//g++ -std=c++14 comp.cpp && ./a.out

// char** arr = new char*[r];
// for(long long i = 0; i < r; i++) arr[i] = new char[c];