#include<bits/stdc++.h> using namespace std; bool x(int n){ if(n<=1)return false; if(n2)return true; if(n%20)return false; for(int i=3;i<=sqrt(n);i+=2){ if(n%i==0)return false; } return true; } int main(){ for(int a=1;a<=9;a++){ for(int b=0;b<=9;b++){ int num=a100+b10+a; if(x(num)){ cout<<num<<endl; } } } return 0; }

#include<bits/stdc++.h>
using namespace std;
int main(){
    cout<<101<<endl;
    cout<<131<<endl;
    cout<<151<<endl;
    cout<<181<<endl;
    cout<<191<<endl;
    cout<<313<<endl;
    cout<<353<<endl;
    cout<<373<<endl;
    cout<<383<<endl;
    cout<<727<<endl;
    cout<<757<<endl;
    cout<<787<<endl;
    cout<<797<<endl;
    cout<<919<<endl;
    cout<<929<<endl;
    return 0;
}