s = gets.chomp.split("")
t = 0
r = 0
e = 0

s.each do |i|

  if i == "t"
    t += 1
  elsif i == "r"
    r += 1
  elsif i == "e"
    e += 1
  else
  end
end

e = e / 2

arr = [t, r, e]
arr.sort!

puts arr[0]