懒得滚动数组优化了

n = int(input())
dp = [999999]*(n+100)
dp[6] = dp[8] = 1
for i in range(9,n+1):
    dp[i] = min(dp[i-6],dp[i-8])
    if dp[i] != 999999:
        dp[i] += 1
print(dp[n] if dp[n] != 999999 else -1)