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 Python (3.4.3) (judge verdict: Runtime Error)

# -*- coding: utf-8 -*-
"""
Created on Sun Jun 17 23:38:43 2018

@author: ashida
"""

N=int(input())

A1 = list( map(int, input().split()))
A2 = list( map(int, input().split()))

SA1 = [0]*N
SA2 = [0]*N

SA1[0] = A1[0]
SA2[N-1] = A2[N-1]

for i in range(N-1):
    SA1[i+1] = SA1[i]+A1[i+1]
    SA2[N-2-i] = SA1[N-1-i]+A1[N-2-i]
    
ans = [0]*N

for i in range(N):
    ans[i] = SA1[i]+SA2[i]

print(max(ans))