#if 1
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>

#define in std::cin
#define out std::cout

char S[1000];

int main()
{
	using std::endl;
	in.sync_with_stdio(false);
	out.sync_with_stdio(false);

	in >> S;
	const char res[] = "yukicoder";
	int i = 0;
	while (res[i] == S[i]) { ++i; }
	out << res[i] << endl;

	return 0;
}
#endif