Update README_EN.md

solution/1800-1899/1845.Seat Reservation Manager/README_EN.md

@@ -178,27 +178,34 @@ func (h *hp) Pop() interface{} {
 
 ### **C#**
 
-```C#
+```cs
 public class SeatManager {
     private SortedSet<int> availableSeats;
+
     public SeatManager(int n) {
         availableSeats = new SortedSet<int>();
-        for (int i = 1; i <= n; i++)
-        {
+        for (int i = 1; i <= n; i++) {
             availableSeats.Add(i);
         }
     }
-
+    
     public int Reserve() {
         int reservedSeat = availableSeats.Min;
         availableSeats.Remove(reservedSeat);
         return reservedSeat;
     }
-
+    
     public void Unreserve(int seatNumber) {
         availableSeats.Add(seatNumber);
     }
 }
+
+/**
+ * Your SeatManager object will be instantiated and called as such:
+ * SeatManager obj = new SeatManager(n);
+ * int param_1 = obj.Reserve();
+ * obj.Unreserve(seatNumber);
+ */
 ```
 
 ### **...**