#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; typedef unsigned long long ull; typedef long double ld; typedef pair P; typedef tuple T; #define vec vector #define vec2 vector #define vec3 vector #define For(i,a,b) for(ll (i) = (a);i < (b);(i)++) #define rep(i,n) For(i,0,n) #define rFor(i,a,b) for(ll (i) = (a-1);i >= (b);(i)--) #define rrep(i,n) rFor(i,n,0) #define each(i,a) for(auto i : a) #define clr(a) memset((a), 0 ,sizeof(a)) #define mclr(a) memset((a), -1 ,sizeof(a)) #define all(a) (a).begin(),(a).end() #define sz(a) (sizeof(a)) #define toint toInt #define tostr toString const int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 }; const int mod = 1000000007; const int INF = 1e9 + 2; template inline T sqr(T x) { return x*x; } template inline T mypow(T x, ll n){ T res = 1; while (n > 0){ if (n & 1)res = res * x; x = x * x; n >>= 1; }return res; } inline int gcd(ll a, ll b){ return b ? gcd(b, a%b) : a; } inline int lcm(ll a, ll b){ return a / gcd(a, b) * b; } inline bool cheak(int x, int y, int xMax, int yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; } inline ll toInt(string s) { ll v; istringstream sin(s); sin >> v; return v; } template inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); } template inline string toString(_RanIt _First, _RanIt _Last, string sep) { if (_First == _Last)return ""; ostringstream sout; sout << *_First; for (_First = next(_First); _First != _Last; _First = next(_First)) { sout << sep << *_First; }return sout.str(); } template inline string toString(_RanIt _First, _RanIt _Last, string sep, string sep2) { if (_First == _Last)return ""; ostringstream sout; sout << toString(all(*_First), sep); for (_First = next(_First); _First != _Last; _First = next(_First)) { sout << sep2 << toString(all(*_First), sep); }return sout.str(); } int main(){ string a, b; cin >> a >> b; if (a.size() > b.size()){ cout << a << endl; return 0; } if (b.size() > a.size()){ cout << b << endl; return 0; } rep(i, a.size()){ if (a[i] == '4' && b[i] == '7'){ cout << a << endl; return 0; } if (a[i] == '7' && b[i] == '4'){ cout << b << endl; return 0; } if (a[i] > b[i]){ cout << a << endl; return 0; } else{ cout << b << endl; return 0; } } return 0; }