diff --git a/WebApp/Coordinate.cs b/WebApp/Coordinate.cs
index 261cb85..e672d4e 100644
--- a/WebApp/Coordinate.cs
+++ b/WebApp/Coordinate.cs
@@ -22,7 +22,7 @@ internal record Coordinate
             }
             else if (item >= '0')
             {
-                col = col * 10 + (item - '0' + 1);
+                col = col * 10 + (item - '0');
             }
         }