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

// Full Adder using 2 Half Adders
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