//判断一个数是素数 //求这个数反转 /** k = 0; n = 1421 n % 10 1 k = k+1;// 1 n = n /10 n % 10 2 k = k * 10 + n % 10//12 n = n /10; n % 10 = 4 k = k * 10 + 4// 124 int n ,k =0; int isss() 反转 is **/ #include<iostream> using namespace std; bool isprime(int n){ if(n == 1){ return false; } for(int i = 2;i<=n/2;i++){ if(n % i == 0)return false; } return true; } int fanz(int n){ int k=0; while(n != 0){ k =k * 10 + n % 10; n = n /10; } return k; } int main(){ int x,y,num=0; cin>>x>>y; for(int i = x;i<=y;i++){ if(isprime(i)){ if(isprime(fanz(i))){ num++; if(num==1){ cout<<i; }else{ cout<<","<<i; } } } } if ( num == 0){ cout<<"No"; } return 0; }