using System;
class MainClass {
public static void Main() {
int[,,] m = new int[3, 3, 3];
int sum = 0;
int n = 1;
for(int x=0; x < 3; x++)
for(int y=0; y < 3; y++)
for(int z=0; z < 3; z++)
m[x, y, z] = n++;
sum = m[0,0,0] + m[1,1,1] + m[2, 2, 2];
Console.WriteLine("Sum of first diagonal: " + sum);
}
}
Sum of first diagonal: 42