diff --git a/src/DataTypes.java b/src/DataTypes.java
index 4f807c1f..aa20b8a3 100644
--- a/src/DataTypes.java
+++ b/src/DataTypes.java
@@ -4,10 +4,10 @@ public class DataTypes {
     // TODO TASK 1: fix this code so that it passes the test in DataTypesTest.java
     public static long sum(List<Integer> numbers) {
 
-        int s = 0;
+        long s = 0;
         // below is a "foreach" loop which iterates through numbers
-        for (int x : numbers) {
-            s += x;
+        for (long x : numbers) {
+            s += x + 1;
         }
         return s;
     }