#include<stdio.h>
int main()
{
int i,j;
int sum=0;
int a[3][3];
for(i = 0; i < 3; i++)
{
for(j = 0; j < 3; j++)
{
scanf("%d", & a[i][j]);
}
}
for(i = 0; i < 3;i++)
{
for(j = 0; j < 3;j++ )
{
if(i==j)
{
sum = sum + a[i][j];
}
}
}
printf("Sum of Digonal matrix element is %d",sum);
return 0;
}