Find a blank field

Find a blank field

Hi

I have set of fields that have some blank values, how to find that and get its line noumbers in output file.

Ex:

Col1 col2 col3
11 ss 103
12   104
13   105  
14 se 106
awk '{if(NF==2)print $1}'
$ cat inputfile
Col1 col2 col3
11 ss 103
12   104
13   105  
14 se 106
$ awk 'NF!=3 {print NR}' inputfile
3
4