Problem:
Score : 100 points

Problem Statement

Given is a lowercase English letter C that is not z. Print the letter that follows C in alphabetical order.

Constraints

C is a lowercase English letter that is not z.

Input

Input is given from Standard Input in the following format:

C

Output

Print the letter that follows C in alphabetical order.

Sample Input 1

a

Sample Output 1

b

a is followed by b.

Sample Input 2

y

Sample Output 2

z

y is followed by z.

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

#include<stdio.h> 
int main(void){
        int N,K,M;
        int array; //格納点数
        int neccesary_num;
        int average_num;
        int i,j,k;

        scanf("%d",&N);
        scanf("%d",&K);
        scanf("%d",&M);

        for(i = 2; i <= N; i++){
                scanf("%d",&array);
                average_num = average_num + array;
        }
        neccesary_num = M * N - average_num;

        //計算処理
        if(neccesary_num > 0){
                if (neccesary_num <= K){
                        printf("%d",neccesary_num);
                }else{
                        neccesary_num = -1;
                        printf("%d",neccesary_num);
                }
        }else{
                neccesary_num = 0;
                printf("%d",neccesary_num);

        }

        return 0;
}