import sequtils

let s = readLine stdin
var cs, ws = newSeq[int]()

for i, v in s:
  if v == 'c': cs.add i
  if v == 'w': ws.add i

if cs.len == 0 or ws.len < 2:
  echo -1
  quit()

ws.keepItIf(it > cs[0])

echo succ ws[1].pred cs[0]