A Prosperous Lot

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本文介绍了一个有趣的数学问题：如何找到一个不超过10^18的正整数n，使得其十进制表示中恰好包含k个环。环是指阿拉伯数字书写形式中封闭的平面区域，例如数字4有一个环，而数字8有两个环。文章提供了一种算法解决方案。

Apart from Nian, there is a daemon named Sui, which terrifies children and causes them to become sick. Parents give their children money wrapped in red packets and put them under the pillow, so that when Sui tries to approach them, it will be driven away by the fairies inside.

Big Banban is hesitating over the amount of money to give out. He considers loops to be lucky since it symbolizes unity and harmony.

He would like to find a positive integer n not greater than 10¹⁸, such that there are exactly k loops in the decimal representation of n, or determine that such n does not exist.

A loop is a planar area enclosed by lines in the digits' decimal representation written in Arabic numerals. For example, there is one loop in digit 4, two loops in 8 and no loops in 5. Refer to the figure below for all exact forms.

$\text{[math]}$

Input

The first and only line contains an integer k (1 ≤ k ≤ 10⁶) — the desired number of loops.

Output

Output an integer — if no such n exists, output -1; otherwise output any such n. In the latter case, your output should be a positive decimal integer not exceeding 10¹⁸.

Examples
InputCopy
2
Output
462
InputCopy
6
Output
8080

#include <cstdio>
#include <algorithm>
#include <bits/stdc++.h>
using namespace std;

// a positive integer n not greater than 10^18
//所以换最多18*2个

int main()
{
    int k;
    int x=8,y=9;
    cin>>k;
    if(k>36)
        printf("-1\n");
    else
    {
        if(k%2)
        {
            cout<<y;
        }
        k/=2;
        while(k--)
            cout<<x;

    }
    return 0;
}