integer::i,c,w,mincww
  character*100::S
  data c,w,mincww/0,0,101/
  read *,S
  do i=1,LEN_TRIM(S)
     if(S(i:i).eq.'c') then
        c = i
        w = 0
     else if (S(i:i).eq.'w') then
        if (w.ne.0) then
           mincww = MIN(mincww, i-c+1)
           c = 0
           w = 0
        else
           w = i
        end if

     end if
  end do
  if (mincww.eq.101) then
     print '(a)',"-1"
  else
     print '(i0)',mincww
  end if
end