s = gets.chomp
min = 101
idx3 = 0

while idx3
  break unless idx1 = s.index('c', idx3)
  break unless idx2 = s.index('w', idx1)
  break unless idx3 = s.index('w', idx2 + 1)

  min = [idx3 - idx1 + 1, min].min
end

puts min == 101 ? -1 : min