diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 49fa7cb..d7fd2f9 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -6,6 +6,5 @@ set(CMAKE_CXX_FLAGS "-g -O2")
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
 
 add_executable(server main.cpp)
-add_executable(advanced advanced.cpp)
 
-# add_executable(client advanced.cpp) # For advanced task
\ No newline at end of file
+add_executable(client advanced.cpp) # For advanced task
\ No newline at end of file
diff --git a/src/include/server.h b/src/include/server.h
index ba56ec5..5456c41 100644
--- a/src/include/server.h
+++ b/src/include/server.h
@@ -39,6 +39,7 @@ int number_of_all_mines;                         // The number of all mines
 void InitMap() {
   using namespace std;
   std::cin >> rows >> columns;
+  assert(2 <= rows && rows <= 30 && 2 <= columns && columns <= 30);
   for (int i = 0; i < rows; i++) {
     cin >> origin_map[i];
     assert(strlen(origin_map[i]) == columns);