using System;
class Program
{
public static string replace_last_occurrence(string s, string subs, string replace) {
int pos = s.LastIndexOf(subs);
if (pos == -1)
return s;
s = s.Remove(pos, subs.Length).Insert(pos, replace);
return s;
}
static void Main() {
string s = "c++ c php c# java golang c# nodejs";
s = replace_last_occurrence(s, "c#", "python");
Console.Write(s);
}
}
/*
run:
c++ c php c# java golang python nodejs
*/