[Algorithm] Count Negative Integers in Row/Column-Wise Sorted Matrix

// Code goes here

function countNegative (M, n, m) {
  count = ;
  i = ;
  j = m - ;

  while (j >= && i < n) {
    if (M[i][j] < ) {
      count += (j+)
      i += ;
    } else {
      j -= ;
    }
  }

  return count;
}

const M = [
  [-,-,-,],
  [-,,,],
  [,,,,]
]
console.log(countNegative(M, M.length, M[].length)) //