Struggerling to undersatnd process of nested for loop with alert result : script and recently asked for help on another matter and it was way more useful then what my teacher told me. So if someone has any spare time to explain the process of the following to me it would be gratefully appreciated. Thanks in advance! 

The alert result is 13 and I'm not sure what the process was to getting it. I understand what the loop does and what += means, however am not sure on their connection or how the second loop effects the result. 

var v=1;

for(i=1;i<5;i++)

  for(j=2;j<5;j++)

    v+=1;
alert(v);