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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#define MOD 1000000007
#define ll long long

int cmpfunc(const void *a, const void *b){
    return (*(int*)a - *(int*)b);
}

int max(int a,int b){
    return (a>b)?a:b;
}

int main(void){
    int n;
    scanf("%d",&n);
    int s[n+1];
    int i;
    for(i=1;i<=n;i++) scanf("%d",&s[i]);
    int ans=0;
    for(i=1;i<=n;i++) ans+=s[i];
    if(ans%10!=0){
        printf("%d\n",ans);
        return 0;
    }

    qsort(s+1,n,sizeof(int),cmpfunc);
    for(i=1;i<=n;i++){
        if(s[i]%10!=0){
            printf("%d\n",ans-s[i]);
            return 0;
        }
    }
    if(i>n) printf("0\n");

    return 0;
}