S = input()

small = 1000

l = len(S)

for i in range(l):
    for j in range(i+1, l):
        for k in range(j+1, l):
            if (S[i] == 'c' and S[j] == 'w' and S[k] == 'w'):
                small = min(small, k-i+1)

if (small == 1000):
    print(-1)
else:
    print(small)