func main()
	var S: []char :: cui@input()
	var c: int :: -1
	var cw: int :: -1
	var ans: int :: ^S + 1
	for i(0, ^S - 1)
		switch(S[i])
		case 'c'
			do c :: i
		case 'w'
			if(cw <> -1)
				do ans :: [ans, (i - cw + 1)].min()
			end if
			do cw :: c
		end switch
	end for
	do ans :: ans = ^S + 1 ?(-1, ans)
	do cui@print("\{ans}\n")
end func