import sys
# sys.setrecursionlimit(10**6)

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)

def solve(op, s, cnt):
    if op == 1:
        n = can_op1(s)
        if n:
            s = op1(s)
            cnt += n
            return solve(2, s, cnt)
        else:
            return cnt
    else:
        if can_op2(s):
            s = op2(s)
            cnt += 1
            c1 = solve(1, s, cnt)
            c2 = 0 if c1 > cnt else solve(2, s, cnt)
            return max(c1, c2)
        else:
            return cnt

S = input()

# ans = 0
# for i in range(1, 2+1):
#     cnt = solve(i, S, 0)
#     # D(cnt)
#     ans = max(ans, cnt)

# print(ans)

ans = 0
for i in range(1, 2+1):
    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)