#include <bits/stdc++.h> using namespace std; bool ss(int n,int m){ int i,s1=0,s2=0; for(i=2;i<n;i++){ if(n%i==0){ s1+=i; } } for(i=2;i<m;i++){ if(m%i==0){ s2+=i; } } if(s1==m&&s2==n) return 1; else return 0; } int main(){ int n,i,j; cin>>n; for(i=2;i<=n;i++){ for(j=2;j<=n;j++){ if(ss(i,j)&&i!=j){ cout<<i<<" "<<j<<endl; } } } return 0; } /************************************************************** Problem: 1140 User: fzy001 Language: C++ Result: Accepted Time:46 ms Memory:2072 kb ****************************************************************/