#!/usr/bin/evn perl

use strict;
use warnings;

my ($sa, $pa, $xa) = split / /, <>;
my ($sb, $pb, $xb) = split / /, <>;

if(length $pa < length $pb) {
	print "$sb\n";
} elsif(length $pa > length $pb) {
	print "$sa\n";
} else {
	my @stra = split //, $pa;
	my @strb = split //, $pb;
	for(my $i = 0; $i < length $pa; $i++) {
		if($stra[$i] < $strb[$i]) {
			print "$sb\n";
			exit;
		} elsif($stra[$i] > $strb[$i]) {
			print "$sa\n";
			exit;
		}
	}
}

print "-1\n";

exit;