#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
bool NOTprime (long long int p){
	int prime = p==1? 0 : 1;
	for(int i=2; i< p ; i++)
		if( p%i == 0 )
			prime = 0;
	return !prime;
}
bool NOTpal (long long int p) {
	char x[100];
	sprintf(x,"%lld",p);
	string s1=x,s2=x;
	reverse(s1.begin(),s1.end());
	return s1 != s2 ;
}
 
int main() {
	long long int p;
	cin>>p;
	for(     ; NOTprime( p ) || NOTpal( p ) ; p++) ;
	cout<< p<<endl; 
	return 0;
}

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