main = do
    s <- getLine
    let n = length s
    let u = zip s [1 .. n]
    let ls = [z - x + 1 | (a, x) <- u, (b, y) <- u, (c, z) <- u, x < y, y < z, a == 'c', b == 'w', c == 'w']
    print $ if null ls then -1 else minimum ls