s = input()
flag_c, flag_w = False, False
start = 0
for i, v in enumerate(s):
    if v == "c" and flag_c == False:
        flag_c = True
        start = i
    if v == "w" and flag_c == True:
        if flag_w == False:
            flag_w = True
        elif flag_w == True:
            print(i - start + 1)
            break
else:
    print(-1)