#include <stdio.h>
#include <string.h>

#define N 1001
#define max(x, y) ((x > y) ? x : y)


int L[N][N];


int lcs_length(char A[N], char B[N]) {
    int i, j, m = strlen(A), n = strlen(B);

    for (i = m; i >= 0; i--) {
        for (j = n; j >= 0; j--) {
            if (A[i] == '\0' || B[j] == '\0') {
                L[i][j] = 0;
            } else if (A[i] == B[j]) {
                L[i][j] = 1 + L[i + 1][j + 1];
                } else {
                L[i][j] = max(L[i + 1][j], L[i][j + 1]);
            }
        }
    }

    return L[0][0];
}


int main () {
    int i = 0, j = 0, m, n, length;
    char a[N], b[N];

    scanf("%s", a);
    scanf("%s", b);

    m = strlen(a);
    n = strlen(b);

    length =  lcs_length(a, b);

    if (length == 0) {
        printf("Empty");

        return 0;
    }

    while (i < m && j < n) {
        if (a[i] == b[j]) {
            printf("%c", a[i]);

            i++;
            j++;
        } else if (L[i+1][j] >= L[i][j+1]) {
            i++;
            } else {
            j++;
        }
    }

    return 0;
}