#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
#include <list>
#include <bitset>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
template<class T> inline T sqr(T x) { return x*x; }
typedef pair<int, int> P;
typedef long long ll;
typedef unsigned long long ull;

#define For(i,a,b)	for(int (i) = (a);i < (b);(i)++)
#define rep(i,n)	For(i,0,n)
#define clr(a)		memset((a), 0 ,sizeof(a))
#define mclr(a)		memset((a), -1 ,sizeof(a))
#define all(a)		(a).begin(),(a).end()
#define rall(a)		(a).rbegin(), (a).rend()
#define sz(a)		(sizeof(a))
#define Fill(a,v)	fill((int*)a,(int*)(a+(sz(a)/sz(*(a)))),v)

bool cheak(int x, int y, int xMax, int yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; }
const int dx[4] = { -1, 0, 1, 0 }, dy[4] = { 0, 1, 0, -1 };
const int mod = 1000000007;
const int INF = 1e9;

int func(string s1,string s2){
	int l1 = s1.size();
	int l2 = s2.size();

	if (l1 > l2)return 1;
	if (l1 < l2)return -1;
	if (l1 == l2){

		rep(i, l1){
			if (s1[i] > s2[i])return 1;
			if (s1[i] < s2[i])return -1;
		}

	}
	return 0;
}

int main()
{
	string sa;
	string pa;
	string xa;
	string sb;
	string pb;
	string xb;
	cin >> sa >> pa >> xa;
	cin >> sb >> pb >> xb;

	if (func(pa , pb) == 1){
		cout << sa << endl;
	}
	if (func(pa, pb) == -1){
		cout << sb << endl;
	}
	if (func(pa, pb) == 0){
		cout << -1 << endl;
	}

	return 0;
}