diff --git a/rooki/src/C166.java b/rooki/src/C166.java
new file mode 100644
index 0000000000000000000000000000000000000000..3be6eaa5353c0814dac882116cca1f701c793232
--- /dev/null
+++ b/rooki/src/C166.java
@@ -0,0 +1,45 @@
+import java.util.Scanner;
+
+public class C166 {
+  public static void main(String[] args) {
+    // 自分の得意な言語で
+    // Let's チャレンジ！！
+    final Scanner sc = new Scanner(System.in);
+    final String line = sc.nextLine();
+
+    // 入力された文字を数値型へ変換
+    int price = Integer.parseInt(line);
+
+    int coincount = 0;
+
+    private static final int COIN_500 = 500;
+    private static final int COIN_100 = 100;
+    private static final int COIN_50 = 50;
+    private static final int COIN_10 = 10;
+    private static final int COIN_5 = 5;
+    private static final int COIN_1 = 1;
+    
+    // 対象の硬貨が何枚必要か計算し、合計枚数に足し合わせる
+    coincount += price / COIN_500;
+
+    // 商品の値段から、既に使用した硬貨の値段分を引く
+    price -= COIN_500 * (price / COIN_500);
+
+    coincount += price / COIN_100;
+    price -= COIN_100 * (price / COIN_100);
+
+    coincount += price / COIN_50;
+    price -= COIN_50 * (price / COIN_50);
+
+    coincount += price / COIN_10;
+    price -= COIN_10 * (price / COIN_10);
+
+    coincount += price / COIN_5;
+    price -= COIN_5 * (price / COIN_5);
+
+    coincount += price / COIN_1;
+    price -= COIN_1 * (price / COIN_1);
+
+    System.out.println(coincount);
+  }
+}