func main()
	var s: []char :: cui@input()
	var t: int :: 0
	var r: int :: 0
	var e: int :: 0
	for i(0, ^s - 1)
		switch(s[i])
		case 't'
			do t :+ 1
		case 'r'
			do r :+ 1
		case 'e'
			do e :+ 1
		end switch
	end for
	var ans: int :: [t, r, e / 2].min()
	do cui@print("\{ans}\n")
end func