------
## 最终结论
```python
def neg_count(lst):
    count = 0
    for num in lst:
        if num < 0:
            count += 1
    return count

# Test cases
assert neg_count([-1, -2, 3, -4, -5]) == 4
assert neg_count([1, 2, 3]) == 0
assert neg_count([1, 2, -3, -10, 20]) == 2
```