Task

Find and display the sum of elements that are below the main diagonal of a matrix.

The matrix should be a square matrix.



 ───   Matrix to be used:   ───


     [[1,3,7,8,10],
      [2,4,16,14,4],
      [3,1,9,18,11],
      [12,14,17,18,20],
      [7,1,3,9,5]] 



int Mat, X, Y, Sum;
[Mat:=  [[1,3,7,8,10],
        [2,4,16,14,4],
        [3,1,9,18,11],
        [12,14,17,18,20],
        [7,1,3,9,5]];
Sum:= 0;
for Y:= 0 to 4 do
  for X:= 0 to 4 do
    if Y > X then
      Sum:= Sum + Mat(Y,X);
IntOut(0, Sum);
]