Stacking Columns - Putting Data In Right Order

I have a question about putting data in the right order. I have this order in my excel files:

City A, City B, City C
10 20 20
20 40 50
15 30 40
45 20 10
50 10 10
20 30 40

I need to put them in order from top to bottom like this:

10
20
15
45
50
20
20
40
30
20
10
30
20
50
40
10
10
40

Is there any way to do this in a fast way. Because I have 440 cities and 13 numbers per city copying and pasting will take a long time..