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]] 



F sumBelowDiagonal(m)
   V result = 0
   L(i) 1 .< m.len
      L(j) 0 .< i
         result += m[i][j]
   R result
 
V m = [[ 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]]
 
print(sumBelowDiagonal(m))