#include <algorithm>
#include <iostream>
#include <set>
#include <string>
using namespace std;
bool Inters(string& line, char& elem) {
    for (size_t i = 0; i < line.size(); ++i) {
        if (line[i] == elem) {
            return true;
        }
    }
    return false;
}
int main() {
    string line;
    set<char> intersection;
    cin >> line;
    for (size_t i = 0; i < line.size(); ++i) {
        intersection.insert(line[i]);
    }
    while (cin >> line) {
        for (char i : intersection) {
            if (!Inters(line, i)) {
                intersection.erase(i);
            }
        }
    }
    if (intersection.size() >0) {
        for (auto i : intersection) {
        cout << i << endl;
        }
    }

    return 0;
}