S = input()
ans = []

for i in range(len(S)):
    if S[i] == 'c':
        c_pos = i
        correct = 0
        for j in range(i + 1, len(S)):
            if S[j] == 'w':
                correct += 1
            if correct == 2:
                ans.append(j - i + 1)
                break
if len(ans) > 0:
    print(min(ans))
else:
    print(-1)