diff --git a/Sheet3/gh_code_Pizzo.pdf b/Sheet3/gh_code_Pizzo.pdf
new file mode 100644
index 0000000..539611f
Binary files /dev/null and b/Sheet3/gh_code_Pizzo.pdf differ
diff --git a/Sheet3/gh_response.txt b/Sheet3/gh_response.txt
new file mode 100644
index 0000000..4d8a1f0
--- /dev/null
+++ b/Sheet3/gh_response.txt
@@ -0,0 +1,16 @@
+* thank you for list of finshed tasks
+
+* g++ -O3 main_blas.cpp bench_funcs_blas.cpp bench_funcs.cpp -lblas
+* g++ -O3 main.cpp bench_funcs.cpp bench_funcs.cpp  ==> problems because *.cpp is included in main file [-1]
+
+* clang-tidy *.cpp -checks=llvm-*,-llvm-header-guard -header-filter=.* -enable-check-profile -extra-arg="-std=c++17" -extra-arg="-fopenmp" -- *.cpp > gh_codecheck.txt
+
+* see also annotated PDF  gh_code_Pizzo.pdf
+* more flexibilty which test to run:
+     See main_blas.cpp and comments   // GH   // HG
+
+* run benchmarks more than once (rule of thumb: 10 sec run time)
+
+
+
+ 
diff --git a/Sheet3/main_blas.cpp b/Sheet3/main_blas.cpp
index 5d7bff1..a87332e 100644
--- a/Sheet3/main_blas.cpp
+++ b/Sheet3/main_blas.cpp
@@ -35,10 +35,15 @@ double toc() {
 }
 
 //CHANGE FLAG BASED ON WHAT YOU WANT TO DO 
-int main() {
+//int main() {
+    //cout << fixed << setprecision(6);
+    //int flag = 2;   // 1=A2 (dot), 2=B2 (matvec), 3=C2 (matmul)
+// GH
+int main(const int argc, const char *argv[])
+{
+    const unsigned int flag = (argc > 1) ? atoi(argv[1]) : 2;    
+// HG
     cout << fixed << setprecision(6);
-    int flag = 2;   // 1=A2 (dot), 2=B2 (matvec), 3=C2 (matmul)
-    
     if (flag == 1) {// A2) DOT via cBLAS
         size_t N = 5000000;
         vector<double> x, y;
@@ -80,7 +85,7 @@ int main() {
     }
 
     else if (flag == 3) { // C2) GEMM via cBLAS
-        size_t M = 500, L = 500, N = 500;
+        size_t M = 500, L = 500, N = 500;        // GH: Use also different sizes
         vector<double> A, B, C;
         gen_matrix_A(M, L, A);
         gen_matrix_A(L, N, B);