def min(a,b); a < b ? a : b; end
S = gets.chomp
ans = S.size * 2
W = S.size.times.select{|i| S[i] == 'w' }.each_cons(2).to_a
C = S.size.times.select{|i| S[i] == 'c' }
C.each do |i|
  w = W.find{|w_| i < w_[0] }
  ans = min(ans, w[1] - i + 1) if w
end
puts ans <= S.size ? ans : -1