prodcart cuv

#include <iostream>
#include <cstring>
using namespace std;
int st[20], card[20], n;
char s[20][20];

void tipar(int k) {
    for (int i = 1; i <= k; i++)
        cout << s[i][st[i] - 1] << ' ';
    cout << endl;
}

int sol(int k) {
    return k == n;
}

void bktr() {
    int k = 1;
    st[k] = 0;
    while (k > 0) {
        if (st[k] < card[k]) {
            st[k]++;
            if (sol(k))
                tipar(k);
            else {
                k++;
                st[k] = 0;
            }
        }
        else
            k--;
    }
}

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> s[i];
        card[i] = strlen(s[i]);
    }
    bktr();
    return 0;
}