#include <iostream>
#include <string>
#include <cctype>
using namespace std;

int main () {
    string s;
    
    if (!(cin >> s)) return 0;
    
    if ((cin >> s) < 0 || (cin >> s) > 100) return 0;
    
    string result = "";
    
    for (char c : s) {
        if (isdigit(c)) {
            result += c;
        }
    }
    
    if (result.empty()) {
        cout << -1 << endl;
    } else {
        cout << result << endl;
    }
    
    return 0;
}