diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index bad9322bb..b0770ec96 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -295,12 +295,12 @@ struct XAigerWriter
 		aig_map[State::S0] = 0;
 		aig_map[State::S1] = 1;
 
-		for (auto bit : ci_bits) {
+		for (auto bit : input_bits) {
 			aig_m++, aig_i++;
 			aig_map[bit] = 2*aig_m;
 		}
 
-		for (auto bit : input_bits) {
+		for (auto bit : ci_bits) {
 			aig_m++, aig_i++;
 			aig_map[bit] = 2*aig_m;
 		}