diff --git a/src/batch.rs b/src/batch.rs
index 4444047..34e5cc4 100644
--- a/src/batch.rs
+++ b/src/batch.rs
@@ -127,8 +127,8 @@ impl Batch {
     ) {
         let this_agent = composition
             .iter()
-            .flat_map(|teams| teams.iter())
-            .flat_map(|team| team.iter())
+            .flatten()
+            .flatten()
             .cloned()
             .collect::<HashSet<_>>();
 
diff --git a/src/history.rs b/src/history.rs
index 1cb4ef6..ea6acab 100644
--- a/src/history.rs
+++ b/src/history.rs
@@ -27,8 +27,8 @@ impl History {
     ) -> Self {
         let this_agent = composition
             .iter()
-            .flat_map(|teams| teams.iter())
-            .flat_map(|team| team.iter())
+            .flatten()
+            .flatten()
             .cloned()
             .collect::<HashSet<_>>();