------
## 最终结论
```python
def add(lst):
    total_sum = 0  # Initialize sum variable
    for index, value in enumerate(lst):  # Iterate over list with indices
        if index % 2 == 1 and value % 2 == 0:  # Check for odd index and even element
            total_sum += value  # Add to sum if conditions are met
    return total_sum  # Return the result
```