text: function biggestElement(matrix) {
      let max = -Infinity;
      for (i = 0; i < matrix.length; i++) {
          for (j = 0; j < matrix[i].length; j++) {
              if (matrix[i][j] > max) {
                  max = matrix[i][j];
              }
          }
      }
       return max;
  }
  
  console.log(biggestElement([[20, 50, 10],
                              [8, 33, 145]]));
  
  console.log(biggestElement([[3, 5, 7, 12],
                              [-1, 4, 33, 2],
                              [8, 3, 0, 4]]));