cww = [-1,-1,-1]

for i, char in enumerate(input()):
    if char == "c":
        cww[0] = i
    if char == "w":
        if cww[1] != -1:
            cww[2] = i
        if cww[0] != -1:
            cww[1] = i
if cww[2] == -1:
    print (-1)
else:
    print(cww[2]-cww[0]+1)