#include <iostream>
#include <string.h>

using namespace std;


int main ()
{
    const string buffer_one = "hello";
    const string buffer_two = "world";

    const int length_one = buffer_one.length();
    const int length_two = buffer_two.length();

    string response;

    for (int i = 0; i < length_one; i++)
    {
        bool find = false;

        for (int j = 0; j < length_two; j++)
        {
            if (buffer_one[i] == buffer_two[j])
            {
                find = true;
                break;
            }
        }

        if (find == false)
        {
            response += buffer_one[i];
        }
    }

    cout << response;

    return 0;
}