# 入力された値を文字列で受け取る
input = gets.chomp

base = input.chars

base.count("t")

# tの数を数える
count1 = base.count("t")
# rの数を数える
count2 = base.count("r")
# eの数を数える
count3 = base.count("e")

a = 0
count1.times do
    puts count1
    puts count2
    puts count3
    if count1 <= count2 || (count1 * 2) <= count3
        count1 = count1 - 1
        count2 = count2 - 1
        count3 = count3 - 1
        a = a + 1
    end
end

puts a