diff --git a/lab6/llvm-pass.so.cc b/lab6/llvm-pass.so.cc
index 6c6e17e..c5a7aea 100644
--- a/lab6/llvm-pass.so.cc
+++ b/lab6/llvm-pass.so.cc
@@ -11,12 +11,30 @@ struct LLVMPass : public PassInfoMixin<LLVMPass> {
 PreservedAnalyses LLVMPass::run(Module &M, ModuleAnalysisManager &MAM) {
   LLVMContext &Ctx = M.getContext();
   IntegerType *Int32Ty = IntegerType::getInt32Ty(Ctx);
+  Type *Int8PtrTy = Type::getInt8PtrTy(Ctx);
+  
   FunctionCallee debug_func = M.getOrInsertFunction("debug", Int32Ty);
   ConstantInt *debug_arg = ConstantInt::get(Int32Ty, 48763);
 
   for (auto &F : M) {
     errs() << "func: " << F.getName() << "\n";
+    if (F.getName() == "main") {
+      IRBuilder<> Builder(&*F.getEntryBlock().getFirstInsertionPt());
 
+      Builder.CreateCall(debug_func, debug_arg);
+
+      Argument *ArgcArg = F.getArg(0);
+      ArgcArg->replaceAllUsesWith(debug_arg); 
+
+      Argument *ArgvArg = F.getArg(1); 
+      Value *GEP = Builder.CreateInBoundsGEP(
+          Int8PtrTy,
+          ArgvArg,
+          ConstantInt::get(Int32Ty, 1)
+      );
+      Value *StrVal = Builder.CreateGlobalStringPtr("hayaku... motohayaku!");
+      Builder.CreateStore(StrVal, GEP);
+    }
   }
   return PreservedAnalyses::none();
 }