C++ :

#include <iostream>
#include <cstring>
using namespace std;
int main()
{
    string s;
    cin >> s;
    if (s.find("er", s.size()-2) != -1) s = s.substr(0, s.size()-2);
    else if (s.find("ly", s.size()-2) != -1) s = s.substr(0, s.size()-2);
    else if (s.find("ing", s.size()-3) != -1) s = s.substr(0, s.size()-3);
    cout << s << endl;
    return 0;
}