#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<int,int> pii; #define FOR(i,a,n) for(int i=a;i<(int)(n);i++) #define REP(i,n) FOR(i,0,n) #define ALL(a) (a).begin(),(a).end() #define MP(a,b) make_pair(a,b) #define PB(a) push_back(a) #define F first #define S second const int INF = 2000000000; const int DX[4]={0,1,0,-1}, DY[4]={-1,0,1,0}; struct P{int x;int y;P(int X=0,int Y=0){x=X;y=Y;}}; int main() { string sa,sb,xa,xb,pa,pb; cin >> sa >> pa >> xa >> sb >> pb >> xb; if(pa.size()>pb.size()) cout << sa << endl; else if(pa.size()<pb.size()) cout << sb << endl; else { REP(i,pa.size()) { if(pa[i]!=pb[i]) { cout << ((pa[i]-'0')>(pb[i]-'0')?sa:sb) << endl; return 0; } } cout << -1 << endl; } return 0; }