n = input()
min_len = float('inf')
found = False

for i in range(len(n)):
    if n[i] == 'c':
        for j in range(i + 1, len(n)):
            if n[j] == 'w':
                for k in range(j + 1, len(n)):
                    if n[k] == 'w':
                        found = True
                        min_len = min(min_len, k - i + 1)
                        break

if found:
    print(min_len)
else:
    print(-1)