import re
import sys
# sys.stdin = open('c.txt')

pm = 'phnom'
ph = 'penh'
can_op1 = lambda s: pm in s
can_op2 = lambda s: 'h' in s or 'e' in s
tr = str.maketrans('e', 'h', 'h')
op1 = lambda s: s.replace('phnom', 'penh')
op2 = lambda s: s.translate(tr)

S = input()

ans = 0
for i in range(1, 2+1):
    s = S
    op = i
    cnt_op1 = cnt_op2 = 0
    cnt_op1_op1 = 0
    while True:
        if op == 1:
            before = len(s)
            s = op1(s)
            after = len(s)
            if after < before:
                cnt_op1 += before - after
                s = op2(s)
                cnt_op2 += 1
                cnt_op1_op1 += 1
                if cnt_op1_op1 == 2:
                    match = re.findall('(phn(om)+)', s)
                    if match:
                        max_c = 0
                        for m in match:
                            c = (len(m[0])-3)//2
                            cnt_op1 += c
                            max_c = max(max_c, c)
                        cnt_op2 += max_c
                    cnt_op2 += 1
                    break
            else:
                op = 2
        else:
            if can_op2(s):
                s = op2(s)
                cnt_op2 += 1
                op = 1
            else:
                break
    ans = max(ans, cnt_op1 + cnt_op2)

print(ans)