import sys

def solve():
    S = input()
    i = S.find('?')
    print('yukicoder'[i])

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

if __name__ == '__main__':
    solve()