import java.util.*;
import java.io.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class No0201 {
    
    static final Scanner in = new Scanner(System.in);
    static final PrintWriter out = new PrintWriter(System.out,false);

    static void solve() {
        String a = in.next();
        String x = in.next();
        in.next();
        String b = in.next();
        String y = in.next();
        in.next();

        if (x.length() != y.length()) {
            out.println(x.length() > y.length() ? a : b);
            return;
        }

        for (int i=0; i<x.length(); i++) {
            if (x.charAt(i) != y.charAt(i)) {
                out.println(x.charAt(i) > y.charAt(i) ? a : b);
                return;
            }
        }

        out.println("-1");
    }

    public static void main(String[] args) {
        long start = System.currentTimeMillis();

        solve();
        out.flush();

        long end = System.currentTimeMillis();
        //trace(end-start + "ms");
        in.close();
        out.close();
    }

    static void trace(Object... o) { System.out.println(deepToString(o));}
}