import sys
from collections import defaultdict

try:
    import mydebug

    def dprint(*objects):
        print(*objects)
except:
    def dprint(*objects, sep='', end='\n'): pass

s = input()
dic = defaultdict(int)

for c in s:
    dic[c] += 1

ans = min(dic["t"], dic["e"]//2)
print(ans)