diff --git a/stopwatch.py b/stopwatch.py
new file mode 100644
index 0000000..88659aa
--- /dev/null
+++ b/stopwatch.py
@@ -0,0 +1,10 @@
+n = int(input())
+if n % 2 != 0:
+    print("still running")
+else:
+    seconds = 0
+    for _ in range(0, n, 2):
+        a, b = map(int, (input(), input()))
+        seconds += b - a
+    print(seconds)
+5
\ No newline at end of file