module adder(SUM, COUT, A, B, CIN);
     input A, B, CIN;
	  output SUM, COUT;
	  
	  wire x;
	  
	  
	  xor x0(x, A, B);
	  xor x1(SUM, x, CIN);
	  
	  assign COUT=x? CIN: B;
	  
endmodule

module