diff --git a/scripts/generate_chat_stat_daily.py b/scripts/generate_chat_stat_daily.py
index e433de6..739977c 100644
--- a/scripts/generate_chat_stat_daily.py
+++ b/scripts/generate_chat_stat_daily.py
@@ -70,7 +70,7 @@ def main():
       if uniqueUserGlobal[id] == None:
         uniqueUserGlobal[id] = []
       labels[id] = begin.strftime("%x")
-      print(f"\t{labels[id]}")
+      print("\t{0}".format(labels[id]))
       
       resultMess = list(filter(filter_message, messages))
       length = len(resultMess)
diff --git a/scripts/generate_chat_stat_monthly.py b/scripts/generate_chat_stat_monthly.py
index 34fc9c8..d8181b6 100644
--- a/scripts/generate_chat_stat_monthly.py
+++ b/scripts/generate_chat_stat_monthly.py
@@ -70,8 +70,8 @@ def main():
       if uniqueUserGlobal[id] == None:
         uniqueUserGlobal[id] = []
       labels[id] = begin.strftime("%b %Y")
-      print(f"\t{labels[id]}")
-      
+      print("\t{0}".format(labels[id]))
+
       resultMess = list(filter(lambda mess: begin < datetime.strptime(mess["ts"], "%Y-%m-%dT%H:%M:%S.%fZ") < end, messages))
       length = len(resultMess)
       dataMess.append(length)