Hi!
Let's make a quick debug of the code:
i   j  Output
0+0 = Â 0 Â
0+1 = Â Â 1
0+2 = Â 2
0+3 = Â 3
1+0 = Â 1Â
1+1 = Â Â 2
1+2 = Â 3
1+3 = Â 4
2+0 = Â 2 Â
2+1 = Â Â 3
2+2 = Â 4
2+3 = Â 5
3+0 = Â 3 Â
3+1 = Â 4
3+2 = Â 5
3+3 = Â 6
4+0 = Â 4 Â
4+1 = Â 5
4+2 = Â 6
4+3 = Â 7
The total outputs is 20.
Explanation:
In the first iterations of the loop for the final value of the i is 1 and the final condition to stop of the do while is (i < 5) , so the iteration of for continues many times until  i break the condition. Â
(5*4 = 20)
And after that you get 20 outputs.
I hope it's help you.