module top(o1, o2, o3);
output wire o1;
`define COND_1
`define COND_2
`define COND_3
`ifdef COND_1
output wire o2;
`elsif COND_2
input wire dne1;
`elsif COND_3
input wire dne2;
`else
input wire dne3;
`endif
output wire o3;
endmodule