56 +
57 1
58 2
59 3
60 4
61 -hello world
61 hello world
62 -goodbye world
63 +hello world
64 + goodbye world
63 + goodbye world
65 7
64 7
66 8
65 8
67 9
66 9
68 % qdiff -U 1 -B
67 % qdiff -U 1 -B