#include <iostream>
using namespace std;
int main()
{
int a, b, max = -100000000, min = 100000000;
cin >> a >> b;
while (a != 0)
{
int c = a % 10;
if (c > max)
{
max = c;
}
a = a / 10;
}
while (b != 0)
{
int c = b % 10;
if (c < min)
{
min = c;
}
b = b / 10;
}
cout << max << min;
}