diff --git a/benchmark.cpp b/benchmark.cpp
index c87e224..9f7d9ed 100644
--- a/benchmark.cpp
+++ b/benchmark.cpp
@@ -17,9 +17,22 @@ static void BM_area_computation(benchmark::State& state) {
     state.SetComplexityN(state.range(0));
 }
 
+static std::vector<Rectangle> get_inst() {
+    srand(17);
+    static std::vector<Rectangle> rects = get_random_instance(1 << 18, 1<<20);
+    return rects;
+}
+
+static void BM_single(benchmark::State& state) {
+    for(auto _ :state) {
+        get_area_union(get_inst());
+    }
+}
+
+BENCHMARK(BM_single);
+
 // add benchmark
 // BENCHMARK(BM_area_computation)->ArgsProduct({benchmark::CreateRange(1<<4,1<<18,4),{1<<20}})->Complexity(benchmark::oNLogN);
-BENCHMARK(BM_area_computation)->Args({{1<<18, 1<<20}});
 
 // run benchmark as main()
 int main(int argc, char **argv) {