C++ :

#include<iostream>
#include<cmath>
using namespace std;
int main(){
	int a,b,cnt=0;
	cin>>a>>b;
	for (int i=a; i<=b; i++){
		int sum=1,t=sqrt(i);
		for (int j=2; j<=t; j++)
			if (i%j==0) sum+=j+i/j;
		if (t*t==i) sum-=t;
		int k=1;
		t=sqrt(sum);
		for (int j=2; j<=t; j++)
			if (sum%j==0) k+=j+sum/j;
		if (t*t==sum) k-=t;
		if (k==i && i<sum){
			cout<<i<<" "<<sum<<endl;
			cnt++;
		}
	}
	if (!cnt) cout<<"No"<<endl;
	return 0;
}