What is the value of sum after the following code segment is executed?

int[][] cells = {
{4, 1, 7},
{6, 5, 3},
{2, 8, 0}
};

int sum = 0;
for (int x = 0; x < cells.length; x++) {
      sum += cells[x][cells[0].length - 1 - x];
}