#include <stdio.h>

int main(void)
{
	char sa[100];
	char sb[100];
	unsigned long long pa;
	unsigned long long pb;
	char xa;
	char xb;
	scanf("%s%lld%c",sa,&pa,&xa);
	(void)getchar();
	scanf("%s%lld",sb,&pb);
	(void)getchar();
	scanf("%c",&xb);
	if(pa>pb){
		printf("%s\n",sa);
	}else if(pa<pb){
		printf("%s\n",sb);
		
	}else if(pa==pb){
		printf("-1\n");
	}
	
	return 0;
}