#include <iostream>
using namespace std;
bool yes(int a){
	if(a==0||a==1) return false;
	for(int i=2;i<a;i++){
		if(a%i==0)return false;
	}
	return true;
}
int main() {
	int n;
	cin>>n;
	int** a=new int*[n];
	for(int i=0;i<n;i++){
		a[i] =new int[n];
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			cin>> a[i][j];
			if((yes(a[i][j]))&&(yes(i+j)==false))cout<<a[i][j];
		}
	}
	for(int i=0;i<n;i++){
		delete[] a[i];
	}
	delete[] a;
	return 0;
 
}

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3
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