import sequtils, strutils

var
    s = readLine(stdin)
    first = -1
    last = -1

proc main():int =
    for i,v in s:
        if v == 'c':
            first = i
        elif v == 'w' and first != -1:
            if last != -1:
                return (i + 1) - first
            last = i
    return -1

echo main()