S = input()
cwls = [None, None, None]
cww = "cww"
a = 0

for i in range(len(S)):
    if S[i] == cww[a] and cwls[a] == None:
        cwls[a] = i
        a += 1
        if a == 3:
            break

if None in cwls:
    print(-1)
else:
    print(cwls[2] - cwls[0] + 1)