#include <iostream>
#include <string>
using std::cout;
using std::endl;
using std::string;
int main()
{
string s = "c, c++, java, python";
std::size_t doubleSpace = s.find(" ");
while (doubleSpace != string::npos)
{
s.erase(doubleSpace, 1);
doubleSpace = s.find(" ");
}
cout << s << endl;
return 0;
}
/*
run:
c, c++, java, python
*/