diff --git a/main.cpp b/main.cpp
index 23dad52..2e4afe2 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,8 +6,19 @@
 
 int main() {
     srand(987192345);
+
+    std::vector<Rectangle> rects;
+    rects.push_back({{0,0},{10,10},0,0});
+    Unit area = get_area_union(rects);
+    assert(area == 10);
+
+    rects.push_back({{2,3},{4,12},0,0});
+    area = get_area_union(rects);
+    std::cout << "Area is " << area << std::endl;
+    assert(area == 14);
+
     std::vector<Rectangle> inst1 = get_random_instance(10,100);
-    Unit area = get_area_union(inst1);
+    area = get_area_union(inst1);
     std::cout << "Area is " << area << "." << std::endl;
     assert(area == 6559);
     return 0;