求救：为什么这段代码总是WA掉

#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<string>
#include<queue>
#include<map>
#include<vector>
#include<algorithm>
#include<set>
#include<iomanip>
#define maxn 10010000

using namespace std;

inline int read(){
	char ch=getchar();
	int x=0,f=1;
	while(ch<'0'||ch>'9'){
		if(ch=='-')f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*f;
}

void write(int x){
	if(x>=10){
		write(x/10);
	}
	putchar(x % 10 + 48);
}

int x[maxn],list[maxn],cnt,vis[maxn],a[maxn];

bool check(int x){
	while(x!=0){
		if(x%10==7)return false;
		x/=10;
	}
	return true;
}

void init(){
	for(int i=1;i<=maxn;++i){
		if(vis[i]==-1)continue;
		if(vis[i]==0){
			if(check(i)){
				vis[i]=++cnt;
				list[cnt]=i;
			}
			else for(int j=1;i*j<=maxn;++j)vis[i*j]=-1;
		}
	}
}

int main(){
	init();
	int n=read();
	for(int i=1;i<=n;++i)a[i]=read();
	for(int i=1;i<=n;++i){
		if(vis[a[i]]==-1)printf("-1\n");
		else printf("%d\n",list[vis[a[i]]+1]);
	}
	return 0;
}