S = input()
correct = 0
pos_c = 0
for i in range(len(S)):
    if correct == 0 and S[i] == 'c':
        correct += 1
        pos_c = i
    elif S[i] == 'w' and correct > 0:
        correct += 1
    elif correct == 3:
        print(i - pos_c)
        break

if correct != 3:
    print('-1')