#include<stdio.h> #include<math.h> int find(int x){ int sum=0,i,t=sqrt(x); for ( i=2; i<=t; i++) if (x%i==0) sum+=i+x/i; if (t*t==x) sum-=t; return sum; } int main(){ int n,a,b,c; scanf("%d",&n); for ( a=2; a<=n; a++){ b=find(a); c=find(b); if (a==c && a!=b && b<=n) printf("%d %d\n",a,b); } return 0; } /************************************************************** Problem: 1140 User: admin Language: C Result: Accepted Time:14 ms Memory:1144 kb ****************************************************************/