$(20$ points$)$ Consider the FUN language, prove the following expression evaluates to $3$ with respect to theSyntax of the FUN Language

Consider a more realistic language called FUN with the following syntax

where $c$ is an Int constant, $b$ is a Bool constant, and $x$ is an Identifier

So far we have learned how to give operational semantics to program

constructs in this language except let bindings

big$-$step operational semantics that can handle recursion.

let $x=2inx+1$