#include <stdio.h>

int main(void){
    char SA[100], SB[100], XA, XB;
    int PA, PB;
    scanf("%s %d %c %s %d %c", &SA, &PA, &XA, &SB, &PB, &XB);
    if(PA>PB){
    	printf("%s\n", SA);
    }else if(PA==PB){
		printf("-1\n");
    }else{
    	printf("%s\n", SB);
    }
    return 0;
}