代码如下

#include<bits/stdc++.h>
using namespace std;
bool book[10000001];
void prime(int b) {
    memset(book, true, sizeof(book));
    book[1]=false;
    int n=sqrt(b);
    for (int i=2;i<=n;i++) {
        if (book[i]) {
            for (int j=2;j<=b/i;j++)
                book[i*j]=false;
        }
    }
}
int main(){
	cin.tie(0);
	cout.tie(0);
	int a,b,num;
	bool x=true;
	string numStr;
	cin>>a>>b;
	if(b>=10000000){
		b=9999999;
	}
	prime(b);
	for(int i=int(a/2)*2+1;i<b;i+=2){
		if((i==1000)||(i==100000)){
			i=i*10;
		}
		if(book[i]){
			numStr=to_string(i);
			num=numStr.length();
			for(int j=0;j<int(num/2);j++){
				if(numStr[j]!=numStr[num-j-1]){
					x=false;
					break;
				}
			}
			if(x==true){
				cout<<i<<endl;
			}
		}
		x=true;
	}
	return 0;
}