S = input()

L = []
for i, s in enumerate(S):
    if s == 'c':
        for j, t in enumerate(S[i+1:]):
            if t == 'w':
                for k, u in enumerate(S[i+j+2:]):
                    if u == 'w':
                        L.append([i, i+j+1, i+j+k+2])
                        break

if len(L) == 0:
    print(-1)

else:
    ans = []
    for a, b, c in L:
        ans += [c-a+1]
    print(min(ans))