import sys

def D(*a, **kwa):
    print(*a, file=sys.stderr, **kwa)

pm = 'phnom'
ph = 'penh'
can_op1 = lambda s: pm in s
op1_cnt = lambda s: s.count(pm)
can_op2 = lambda s: 'h' in s or 'e' in s

tr = str.maketrans('e', 'h', 'h')
op1 = lambda s: s.replace(pm, ph)
op2 = lambda s: s.translate(tr)

s = input()

ans = 0
for i in range(1, 2):
    op = i
    cnt = 0
    # s = S
    while True:
        if op == 1:
            n = op1_cnt(s)
            if n:
                s = op1(s)
                cnt += n
            op = 2
        else:
            if can_op2(s):
                s = op2(s)
                cnt += 1
                op = 1
            else:
                break
    ans = max(ans, cnt)

print(ans)