#include<bits/stdc++.h> using namespace std; int yinzihe(int n){ int s=0; for(int i=2;i<=n-1;i++){ if(n%i==0){ s+=i; } } return s; } int main(){ int k; cin>>k; for(int i=2;i<=k;i++){ for(int j=2;j<=k;j++){ if(yinzihe(i)==j&&yinzihe(j)==i){ cout<<i<<" "<<j<<endl; } } } return 0; } /************************************************************** Problem: 1140 User: luyanchen Language: C++ Result: Accepted Time:30 ms Memory:2072 kb ****************************************************************/