diff --git a/AcWing/4317/4317.cpp b/AcWing/4317/4317.cpp
new file mode 100644
index 00000000..4c395e06
--- /dev/null
+++ b/AcWing/4317/4317.cpp
@@ -0,0 +1,20 @@
+#include <iostream>
+#include <set>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int n;
+std::set<int> set;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> n;
+    for (int i = 1, x; i <= n; i++) {
+        cin >> x;
+        if (x > 0) set.insert(x);
+    }
+    cout << set.size() << endl;
+    return 0;
+}