9. XOR Gate Using Basic Gates

How do you plan to solve it?

// ============================================================
// Basic Gates (given)
// ============================================================
module and_gate(input a, b, output y);
    assign y = a & b;
endmodule

module or_gate(input a, b, output y);
    assign y=a|b;
endmodule

module not_gate(input a, output y);
    assign y=~a;
endmodule

// ============================================================
// XOR Gate
// ============================================================
module xor_gate (
    input  a, b,
    output y
);
    wire p,q,r,s;
    not_gate n1(.a(a), .y(p));
    not_gate n2(.a(b), .y(q));
    and_gate a1(.a(a), .b(q), .y(r));
    and_gate a2(.a(p), .b(b), .y(s));
    or_gate  o1(.a(r), .b(s), .y(y));

endmodule