this is line 1
this is line 2
this is line 3
this is line 4
this is line 5
only left file change one line
this is line 7
this is line 8
this is line 9
this is line 10
this is line 11
only left file changed five lines but the third and fourth is deleted
changed line number 2
changed line number 5 and 2 prev lines are deleted
this is line 17
this is line 18
this is line 19
this is line 20
