diff --git a/Luogu/problem/B2021/B2021.cpp b/Luogu/problem/B2021/B2021.cpp
new file mode 100644
index 00000000..558adaea
--- /dev/null
+++ b/Luogu/problem/B2021/B2021.cpp
@@ -0,0 +1,10 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main() {
+    float a;
+    cin >> a;
+    cout << fixed << setprecision(3) << a << endl;
+    return 0;
+}