S = input()
ans = 200
for i in range(len(S)):
    if(S[i] != 'c'):
        continue
    for j in range(i+1, len(S)):
        if(S[j] != 'w'):
            continue
        for k in range(j+1, len(S)):
            if(S[k] != 'w'):
                continue
            ans = min(ans, k-i+1)
if ans == 200:
    print(-1)
else:
    print(ans)