`timescale 1ns/1ns module main_mod( input clk, input rst_n, input [7:0]a, input [7:0]b, input [7:0]c, output [7:0]d ); wire [7:0] d0,d1,d2; min_num u0 ( .clk (clk) , .rst_n (rst_n), .a(a), .b(b), .c(d0) ); min_num u1 ( .clk (clk) , .rst_n (rst_n), .a(b), .b(c), .c(d1) ); min_num u2 ( ....