#include <iostream>
#include <string>
using namespace std;
int main() {
    string s,ans;
    cin>>s;
    for(int i=0;i<s.length();i++){
        if(s[i]>='0' and s[i]<='9'){
            ans += to_string(i);
        }
    }
    cout<<ans<<'\n';
    return 0;
}