`timescale 1ns/1ns module top_module ( input a, input b, input c, input d, output e, output f ); wire r_and,r_or; assign r_and=a&b; assign r_or=c|d; assign f=r_and^r_or; assign e=r_and~^r_or;//~(a^b)=a~^b; endmodule