diff --git a/day4.cs b/day4.cs
index 4cbb5b5..de7e1c4 100644
--- a/day4.cs
+++ b/day4.cs
@@ -48,7 +48,7 @@ class day4
 
         foreach(Field field in fields)
         {
-            field.markNumber("1");
+            field.markNumber("13");
             field.printField();
             field.checkBingo();
             
@@ -76,7 +76,7 @@ class Field{
         {
             for (int j = 0; j < 5; j++)
             {
-                if (bingoField[i, j].Contains(markNumber))
+                if (bingoField[i, j].Contains($"[{markNumber}]"))
                 {
                     bingoField[i, j] = $"[X{markNumber}]";
                 }