Problem:
Score : 100 points

Problem Statement

You are given two integers A and B as the input. Output the value of A + B.

However, if A + B is 10 or greater, output error instead.

Constraints

A and B are integers.

1 ≤ A, B ≤ 9

Input

Input is given from Standard Input in the following format:

A B

Output

If A + B is 10 or greater, print the string error (case-sensitive); otherwise, print the value of A + B.

Sample Input 1

6 3

Sample Output 1

9

Sample Input 2

6 4

Sample Output 2

error

Solution in C (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
int cmp(const void *c1, const void *c2 )
{
  int tmp1 = *(int *)c1;
  int tmp2 = *(int *)c2;

  if( tmp1 < tmp2 )  return -1;
  if( tmp1 == tmp2 ) return  0;
  if( tmp1 > tmp2 )  return  1;
}
int main(void)
{
    int N;
    int score;
    int sum = 0;
    bool flag = true;

    scanf("%d", &N);
    int *scores;
    scores = malloc(sizeof(int) * N);
    for (int i = 0; i < N; ++i) {
        scanf("%d", &score);
        sum += score;
        scores[i] = score;
        if (flag && score % 10 != 0)
            flag = false;
    }
    if (flag) {
        puts("0");
        return 0;
    }
    if (sum % 10 == 0) {
        qsort(scores, N, sizeof(int), cmp);
        //for (int i = 0; i < N; i++)
        //    printf("%d ", scores[i]);
        for (int i = 0; i < N && sum % 10 == 0; i++) {
            //printf("[[%d\n", scores[i]);
            sum -= scores[i];
        }
    }
    printf("%d\n", sum);
    return 0;
}