#include <iostream>
using namespace std;

int sum(int n );

int main()
{
   int a, b;
   cout << "Enter 2 positive integers a <= b: " << flush;
   cin >> a >> b;
   
   int c = b;   
   int d = a;
   int tmp;
   
   for( int n = a; n <= b; n++ )
   {
      tmp = n - sum(n);    
      if( tmp < 0 ) 
        tmp = -tmp;
   
          if( tmp <= c )
              tmp = c;
                d = n;  
   }
   
   cout << "The distance is minimal for "  << d << " and is equal to " << min << endl;
    
   system("pause");
   return 0;
}

// ----------------------------- //

int sum( int n )
{
   int s = 1;
   // if d is a divisor of n so is n/d avoid to search till n
   for( int d = 2; d*d <= n; d++ )
     if( n%d == 0 )
       s += d + n/d;    
   return s; 
}

cout << "The distance is minimal for "  << d << " and is equal to " << min << endl;

 for( int d = 2; d*d <= n; d++ )
     if( n%d == 0 )
       s += d + n/d;