diff --git a/engine.json b/engine.json
index c51e5ec..8905191 100644
--- a/engine.json
+++ b/engine.json
@@ -13,7 +13,7 @@
       "params": {
         "seed": 1,
         "rank": 10,
-        "iteration": 30,
+        "iteration": 10,
         "lambda": 0.01,
         "appName": "javadase",
         "similarItemEvents": ["view"]
diff --git a/src/main/java/org/template/recommendation/Algorithm.java b/src/main/java/org/template/recommendation/Algorithm.java
index 0fd4c59..3785018 100644
--- a/src/main/java/org/template/recommendation/Algorithm.java
+++ b/src/main/java/org/template/recommendation/Algorithm.java
@@ -136,15 +136,20 @@
             public Boolean call(Tuple2<Tuple2<Integer, Integer>, Integer> element) throws Exception {
                 return (element != null);
             }
+        }).mapToPair(new PairFunction<Tuple2<Tuple2<Integer,Integer>,Integer>, Integer, Integer>() {
+            @Override
+            public Tuple2<Integer, Integer> call(Tuple2<Tuple2<Integer, Integer>, Integer> element) throws Exception {
+                return new Tuple2<>(element._1()._2(), element._2());
+            }
         }).reduceByKey(new Function2<Integer, Integer, Integer>() {
             @Override
             public Integer call(Integer integer, Integer integer2) throws Exception {
                 return integer + integer2;
             }
-        }).map(new Function<Tuple2<Tuple2<Integer, Integer>, Integer>, ItemScore>() {
+        }).map(new Function<Tuple2<Integer, Integer>, ItemScore>() {
             @Override
-            public ItemScore call(Tuple2<Tuple2<Integer, Integer>, Integer> element) throws Exception {
-                return new ItemScore(indexItemMap.get(element._1()._2()), element._2().doubleValue());
+            public ItemScore call(Tuple2<Integer, Integer> element) throws Exception {
+                return new ItemScore(indexItemMap.get(element._1()), element._2().doubleValue());
             }
         });