Build a $4-$bit saturation adder for unsigned integers. A saturation adder performs normal $4-$bit addition when the resulting sum is less than $15.$ However, if the sum is greater than $15,$ which would normally cause an adder to overflow, the saturation adder$$s sum output should stay at $15.$ The inputs of the saturation adder are two $4-$bit unsigned binary integers A $=$ a$3$a$2$a$1$a$0$ and B $=$ b$3$b$2$b$1$b$0$ and the output is a $4-$bit data output S $=$ s$3$s$2$s$1$s$0.$ First write the behavior of the adder using an if$...$else... statement. Then clearly draw the schematic containing the building blocks and their connections.