C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
    string s,r = "";
    cin>>s;
    int i;
    for(i = s.size() - 1;i >= 0;i--){
        if(s[i] >= 'A' && s[i] <= 'Z'){
            r = r + s[i];
        }
    }
     
     
    for(i = 0;i < s.size();i++){
        if(s[i] >= 'a' && s[i] <= 'z'){
            r = r + s[i];
        }
    }
     
     
    cout<<r;
    return 0;
}

Java :

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc =new Scanner(System.in);
		String a = sc.nextLine();
		
		String xx="";
		for(int i=0;i<a.length();i++){
			char m;
			m=a.charAt(i);
			if(m>='a'&&m<'z'){
				xx=xx+m;
			}
			
		}
		String dx="";
		for(int i=a.length()-1;i>=0;i--){
		
		char z=a.charAt(i);
			if(z>='A'&&z<='Z'){
				dx=dx+z;
			}
		}
		System.out.println(dx+""+xx);
	    

		
		
		
		
		sc.close();
	}
	
	
}