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

int main(void){
	char sa[128],pa[16384],xa[8],sb[128],pb[16384],xb[8];
	int al,bl,i;
	scanf("%s%s%s%s%s%s",sa,pa,xa,sb,pb,xb);
	al = strlen(pa);
	bl = strlen(pb);
	if(al > bl){printf("%s\n",sa);return 0;}
	if(al < bl){printf("%s\n",sb);return 0;}
	for(i = 0;i < al;i++){
		if(pa[i] > pb[i]){printf("%s\n",sa);return 0;}
		if(pa[i] < pb[i]){printf("%s\n",sb);return 0;}
	}
	printf("-1\n");
	return 0;
}