s = input()
l = [(s, 0)]
r = 0
tt = s.maketrans({'h':None, 'e':'h'})
while l:
	nl = []
	while l:
		s, i = l.pop(0)
		if i>=0:
			i = s.find('phnom', i)
			if i>=0:
				nl.append((s[:i]+'penh'+s[i+5:], i+4))
				i += 5
			l.append((s, i))
		else:
			if 'h' in s or 'e' in s:
				nl.append((s.translate(tt), 0))
	l = nl
	r += 1
print(r-1)