#include <bits/stdc++.h> using namespace std; int f(int x) { for(int i = 2; i * i <= x; ++i) { if(x % i == 0){ //cout << x << ' ' << i << endl; //cout << "this" << endl; return 0; } } return 1; } int is_prime(int x) { if(x <= 1) return 0; //for(int i = 2; i * i <= x; ++i) if(!f(x)) return 0; return 1; } int a[100005]; int p; int main() { /*for(int i = 2; i < 20341; ++i) { if(20341 % i == 0) //cout << "20341 isn't prime number." << endl; cout << "20341" << endl; }*/ int m, n; cin >> m >> n; for(int i = m; i <= n; ++i) { //i 第一个数 //反序（倒过来的那个数） 第二个数 int x = i; int j = 0; while(x) { j = j * 10 + x % 10; x = x / 10; } if(is_prime(i) && is_prime(j)) { //cout << i << "=" << is_prime(i) << endl; //cout << j << "=" << is_prime(j) << endl; a[p++] = i; } /*if(is_prime(i) && is_prime(j)) cout << i << ',';*/ } for(int i = 0; i < p; ++i) { if(i != p - 1) cout << a[i] << ','; else cout << a[i] << '\n'; } //if(p == 0) if(!p) cout << "No" << '\n'; return 0; }