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: Accepted)

#include <stdio.h>
	int main(void) {
		int a, b, sum;
		scanf("%d %d", &a, &b);
		if(a>9 || a<1 || b>9 || b<1){
			printf("error.\n");
			return 1;
		}
		sum = a + b;
		if(sum >= 10) printf("error");
		else printf("%d",sum);
		return 0;
	}