How to bring the list to the number?

I have a list like:

a = {1,2,4,3};

And I want to get the & # 39; number & # 39; of the list. For this example, I want to get this number: 1243. I do not know how to get it easily. For now, my solution is:
a[[1]]* 10 ^ 3 + a[[2]]* 10 ^ 2 + a[[3]]* 10 ^ 1 + a[[4]];
Works. But it is too complex. I want to know a more convenient way.