s = input()

c, w1, w2, cnt = 0, 0, 0, 0

for i, v in enumerate(s):
    if v == "c":
        c = i + 1
    elif v == "w":
        cnt += 1
        if cnt == 1:
            w1 = i + 1
        elif cnt == 2:
            w2 = i + 1
if c != 0 and w1 != 0 and w2 != 0:
    print(w2 - c + 1)
else:
    print(-1)