include stdafx include math include iostream using namespace std doubl

#include "stdafx.h" 
#include "math.h" 
#include <iostream> 
using namespace std; 


double f (int ** A, int m)
{  
	int k=0; 
	int sum=0;
	for (int i=0; i<m; i++)
		 for (int j=0;j<i;j++)
		 {
			 sum+=A[i][j];
			 k++;
		 }

	return (double) sum/k;
}

void main() 
{  int m;
 cin>>m;
 int** a= new int* [m];
   for (int i=0;i<m;i++)
	    a[i]=new int [m];

   for (int i=0; i<m; i++)
		 for (int j=0;j<m;j++)
			 cin>>a[i][j];

   cout<<f(a,m);

 for (int i=0;i<m;i++)
	    delete [] a[i];

 
}