diff --git a/AcWing/721/721.cpp b/AcWing/721/721.cpp
new file mode 100644
index 00000000..d33d714a
--- /dev/null
+++ b/AcWing/721/721.cpp
@@ -0,0 +1,15 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n;
+
+int main() {
+    while (cin >> n, n) {
+        for (int i = 1; i <= n; i++) {
+            cout << i << ' ';
+        }
+        cout << endl;
+    }
+    return 0;
+}