data Tree = NilNode | Node Integer Tree Tree

segWidth = 2 ^ 17

segVal NilNode = 0
segVal (Node val _ _) = val

segUpdate = f 0 segWidth
    where
        f l r k v NilNode = f l r k v (Node 0 NilNode NilNode)
        f l r k v (Node val left right)
            | r - l == 1      = Node (val + v) NilNode NilNode
            | otherwise       =
                let mid = (l + r) `quot` 2 in
                if k < mid then
                    let newLeft = f l mid k v left in
                        Node (segVal newLeft + segVal right) newLeft right
                else
                    let newRight = f mid r k v right in
                        Node (segVal left + segVal newRight) left newRight

segQuery = f 0 segWidth
    where
        n = 2 ^ 17
        f l r a b NilNode = 0
        f l r a b (Node val left right)
            | r <= a || b <= l = 0
            | a <= l && r <= b = val
            | otherwise        =
                let mid = (l + r) `quot` 2
                    vl = f l mid a b left
                    vr = f mid r a b right in vl + vr

main = getLine >>= print . solve
    
solve = fst . foldr f (0, NilNode) . flip zip [0..]
    where
        f (v, i) (s, tree)
            | v == 'c'  = let num = segQuery (i + 1) segWidth tree in (s + num * (num - 1) `quot` 2, tree)
            | v == 'w'  = (s, segUpdate i 1 tree)
            | otherwise = (s, tree)