#include<iostream>
#include<string>
using namespace std;
int main()
{
    string s;
    cin>> s;
    string result = "";
    if(s.length() >=1 && s.length() <=100) {
        for( int i=0;i<s.length();i++)
        if(isdigit(s[i])){
            result +=s[i];
        }
    }
    if(result.length() = 0) {
        cout<<-1;
    }else{
        cout<<result;
    }
    return 0;
}