cf462 A Compatible Pair

最新推荐文章于 2021-03-18 20:55:30 发布

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本文介绍了一个寻找特定数量圆环数字的问题，通过算法实现找到一个不超过10^18的正整数，其十进制表示中正好包含k个圆环。

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

Input

Output

Input

Output

#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
#define f(i,l,r) for(int i=l;i<=r;i++)
#define g(i,l,r) for(int i=l;i>=r;i--)
 //888888888888888888 18* 2  === 36

int main()
{
	int n;
	cin>>n;
	if(n>36)cout<<-1<<endl;
	else
	{
		if(n%2==1) cout<<1;
		f(i,1,n/2) cout<<8;
		cout<<endl;
	}
	return 0;
}