import sys
from functools import cache
sys.setrecursionlimit(500000)


@cache
def calc_partial_string(
        all_string: str,
        a_idx: int,
        search_string: str,
        s_idx: int) -> int:
    if s_idx == len(search_string):
        if a_idx <= len(all_string):
            return 1
        return 0

    if len(all_string) - a_idx < len(search_string) - s_idx:
        return 0
    if all_string[a_idx] != search_string[s_idx]:
        return calc_partial_string(all_string, a_idx + 1, search_string, s_idx)

    return calc_partial_string(all_string,
                               a_idx + 1,
                               search_string,
                               s_idx) + calc_partial_string(all_string,
                                                            a_idx + 1,
                                                            search_string,
                                                            s_idx + 1)


def printe(*args, end="\n", **kwargs):
    print(*args, end=end, file=sys.stderr, **kwargs)


def main():
    N = int(input())
    S = input()
    YUKICODER = "yukicoder"
    T = set(YUKICODER[:idx] + "?" + YUKICODER[idx + 1:] for idx in range(9))
    T.add("yukicoder")

    print(sum(calc_partial_string(S, 0, t_elm, 0) for t_elm in T))


if __name__ == "__main__":
    main()