Hi,
You could do this a few different ways, but what looks like it might be the easiest is to move the pickoff point for K1 to the output Y by adding another block 1/s in series with it first. That will still leave you with two feedback paths but you'll still be solving for Y without too much fuss which is the main goal. Once you move that to the output you can combine the two feedback paths easily and then you're left with only one feedback path which should be easy to eliminate.
I assume you already know how to eliminate feedback paths.
Alternately you could combine the feedback paths the way they are and solve for the input to the last block 1/s, then after that solve for the output.
Another alternative is to use Masons Signal Flow Graph Formula.