#include <stdio.h>
#include <string.h>

int main(){
	int val = 0;
	scanf("%d",&val);
	
	char *str1 = "test";
	char *str2 = "test";
	for(int i = 0;i < val;i ++){
		scanf("%s%s",str1,str2);
		int len = 0;
		int len1 = strlen(str1);
		int len2 = strlen(str2);
		if(len1 > len2){
			len = len1;
		}else{
			len = len2;
		}
		for(int j = 0;j < len;j ++){
			if(str1[j] != str2[j]){
				printf("%d\n%s\n%s\n",i + 1,str1,str2);
				return 0;
			}
		}
	}
	
}