S = input()
cnt = 0
m_cnt = 0
for s in S:
    if cnt == 6:
        if s == 'e':
            cnt = 7
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 5:
        if s == 'c':
            cnt = 6
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 4:
        if s == 'n':
            cnt = 5
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 3:
        if s == 'e':
            cnt = 4
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 2:
        if s == 'y':
            cnt = 3
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 1:
        if s == 'e':
            cnt = 2
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
    if cnt == 0:
        if s == 'k':
            cnt = 1 
        else:
            if m_cnt < cnt:
                m_cnt = cnt
            cnt = 0
if m_cnt < cnt:
    m_cnt = cnt
            
cnt2 = 0
m_cnt2 = 0
for s in S[::-1]:
    if cnt2 == 6:
        if s == 'k':
            cnt2 = 7
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0
    if cnt2 == 5:
        if s == 'e':
            cnt2 = 6
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0
    if cnt2 == 4:
        if s == 'y':
            cnt2 = 5
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0
    if cnt2 == 3:
        if s == 'e':
            cnt2 = 4
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0
    if cnt2 == 2:
        if s == 'n':
            cnt2 = 3
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0

    if cnt2 == 1:
        if s == 'c':
            cnt2 = 2
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0

    if cnt2 == 0:
        if s == 'e':
            cnt2 = 1
        else:
            if m_cnt2 < cnt2:
                m_cnt2 = cnt2
            cnt2 = 0
if m_cnt2 < cnt2:
    m_cnt2 = cnt2

if m_cnt + m_cnt2 >=7:
    print('YES')
else:
    print('NO')