diff --git a/1.py b/1.py
new file mode 100644
index 0000000..cc1f5c4
--- /dev/null
+++ b/1.py
@@ -0,0 +1,7 @@
+def sum(n):
+    if n==1:
+        return 1
+    a=sum(n-1)+n
+    return a
+a=sum(10)
+print(a)