Why is this giving me a compile error

fn main() {

    let x = &mut 5;
    //let y = &x;
    let y = &x;
    //*x = *x + 1;

    // y = is address where x is stored
    // y* = x = value of x = address where 5 is stored
    // y** = x* = 5 = literal i32 value 5
    **y = **y + 5; // Giving compile error "error: cannot assign to data in a `&` reference"
    println!("{:p}", y);  // 0x7fff230091e8
    println!("{:p}", *y); // 0x7fff230091e4
    println!("{:p}", x);  // 0x7fff230091e4
}