【补题计划】NOIP 2021

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
#define int long long

using namespace std;

const int maxn=1e7;

inline int read()
{
	int w=0,f=1;
	char ch=getchar();
	while(ch<'0' || ch>'9')
	{
		if(ch=='-')
		{
			f=-1;
		}
		ch=getchar();
	}
	while(ch>='0' && ch<='9')
	{
		w=(w<<3)+(w<<1)+(ch^48);
		ch=getchar();
	}
	return w*f;
}

int T;

int las;

int nex[maxn];

bool sign[maxn];

bool check(int x)
{
	if(x==7)
	{
		return false;
	}
	while(x)
	{
		if(x%10==7)
		{
			return false;
		}
		x/=10;
	}
	return true;
}

signed main()
{
	T=read();
	
	for(int i=1;i<=maxn+5;i++)
	{
		if(sign[i])
		{
			continue;
		}
		if(!check(i))
		{
			sign[i]=true;
			for(int j=i;j<=maxn+5;j+=i)
			{
				sign[j]=true;
			}
			continue;
		}
		nex[las]=i;
		las=i;
	}
	
	while(T--)
	{
		int k=read();
		if(sign[k])
		{
			cout<<-1<<endl;
			continue;
		}
		cout<<nex[k]<<endl;
	}
	
	return 0;
}