import sys

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)
op12 = lambda s: s.replace(pm, ph).translate(tr)
op2 = lambda s: s.translate(tr)

s = input()

op = 1
cnt = 0
while True:
    if op == 1:
        before = len(s)
        s = op1(s)
        after = len(s)
        if after < before:
            s = op2(s)
            cnt += before - after  + 1
        else:
            op = 2
    else:
        if can_op2(s):
            s = op2(s)
            cnt += 1
            op = 1
        else:
            break

print(cnt)