#include <cstring>
#include <iostream>

using namespace std;

const int N = 110;

int t, res, f[N][N];

char a[N], b[N];

int main()
{
    cin >> a + 1 >> b + 1;
    int n = strlen(a + 1), m = strlen(b + 1);
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++)
            if(a[i] == b[j]) 
            {
                f[i][j] = max(f[i][j], f[i - 1][j - 1] + 1);
                if(f[i][j] >= res) t = i;
                    res = max(res, f[i][j]);
            }
    cout << res << '\n';
    for(int i = t - res + 1; i <= t; i ++) cout << a[i];

    return 0;
}