Given this df: 

```
Name  i   j   k   
A     1   0   3
B     0   5   4   
C     0   0   4
D     0       5

```

My goal is to add in a column "Final" that takes value in an order of i j k:

```
Name  i   j   k     Final
A     1   0   3     1      
B     0   5   4     5 
C     0   0   4     4
D     0       5            <-- this one is tricky.  We do count the null for j column here. 

```

Here is my attempt: df['Final'] = df[['i', 'j', 'k'].bfill(axis=1).iloc[:, 0]. This doesn't work since it always takes the value of column 1. Any help would be appreciated. :) 

Many thanks!