diff --git a/AtCoder/ABC251/D/D.cpp b/AtCoder/ABC251/D/D.cpp
new file mode 100644
index 00000000..904a1b15
--- /dev/null
+++ b/AtCoder/ABC251/D/D.cpp
@@ -0,0 +1,27 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cout << 297 << endl;
+
+    for (int i = 1; i <= 99; i++) {
+        cout << i << ' ';
+    }
+
+    for (int i = 100; i <= 9900; i += 100) {
+        cout << i << ' ';
+    }
+
+    for (int i = 10000; i <= 990000; i += 10000) {
+        cout << i << ' ';
+    }
+
+    cout << endl;
+
+    return 0;
+}