diff --git a/comblogic/fadderstr.v b/comblogic/fadderstr.v
new file mode 100644
index 0000000..657d58c
--- /dev/null
+++ b/comblogic/fadderstr.v
@@ -0,0 +1,11 @@
+`include "hadf.v"
+module fadd(a,b,cin,sum,cout);
+input a,b,cin;
+output sum,cout;
+wire s1,c1,c2;
+hadf g1(a,b,s1,c1);
+hadf g2(s1,cin,sum,c2);
+assign cout=c1|c2;
+endmodule
+
+