64. Full Adder

How do you plan to solve it?

// Half Adder primitive
module half_adder (
    input  a, b,
    output sum, carry
);
    xor(sum,a,b);
    and (carry,a,b);
    
endmodule

module full_adder_struct (
    input  a, b, cin,
    output sum, cout
);
    wire sum1,carry1,carry2;

    half_adder ha1(.a(a), .b(b), .sum(sum1), .carry(carry1));
    half_adder ha2(.a(sum1), .b(cin), .sum(sum),  .carry(carry2));
     
    or (cout,carry1,carry2);
endmodule