S = input()
N = len(S)
ans = -1
for i in range(N):
    if S[i] == "c":
        w = 0
        for j in range(i+1, N):
            if S[j] == "w":
                w += 1
                if w == 2:
                    l = j - i + 1
                    if ans==-1 or l < ans:
                        ans = l
                        break
print(ans)