#include <stdio.h>
#include <stdlib.h>
#define N 5
double fun ( int w[][N] )
{
int i,j;
double ave,sum=0;
for(i=0;i<N;i++)
sum+=w[i][0]+w[i][N-1];
for(j=0;j<N;j++)
sum+=w[0][j]+w[0][j];
sum-=(w[0][0]+w[0][N-1]+w[N-1][0]+w[N-1][N-1]);
ave=sum/(4*N-4);
return ave;
}
