S = list(input())

c = [0] * len(S)
w = [0] * len(S)
ans = 1000

for i in range(len(S)):
    if S[i] == "c":
        c[i] = 1

    if S[i] == "w":
        w[i] = 1

c_count = c.count(1)

for i in range(c_count):
    flag = 0
    w_count = 0
    c_index = c.index(1)
    for j in range(c_index+1, len(S)):
        c[c_index] = 0
        if w[j]:
            w_count += 1

            if w_count == 2:
                ans = min(ans, j - c_index + 1)
                flag = 1
                break

        if flag :
            flag = 0
            break

if ans > 100:
    ans = -1
print(ans)