diff --git a/sitou/src/B146_battle.java b/sitou/src/B146_battle.java
new file mode 100644
index 0000000000000000000000000000000000000000..43585029e46fcb6fd54b5b290cf066c6ad26c65e
--- /dev/null
+++ b/sitou/src/B146_battle.java
@@ -0,0 +1,57 @@
+package src;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Scanner;
+
+public class B147_slime {
+
+  public static void main(String[] args) {
+    Scanner sc = new Scanner(System.in);
+    final int singleAttack = sc.nextInt();
+    final int allAttack = sc.nextInt();
+    final int monsters = sc.nextInt();
+    ArrayList<Integer> monstersHPList = new ArrayList<>();
+
+    for (int i = 0; i < monsters; i++) {
+      monstersHPList.add(sc.nextInt());
+    }
+
+    int count = attackCount(monstersHPList, allAttack, singleAttack);
+    System.out.println(count);
+    sc.close();
+  }
+
+  static int attackCount(ArrayList<Integer> monstersHPList, int allAttack,
+      int singleAttack) {
+    int count = 0;
+
+    while (monstersHPList.size() > 0) {
+      final int maxHP = Collections.max(monstersHPList);
+      final int maxHPIndex = monstersHPList.indexOf(maxHP);
+      int allOnlyCount = (int) Math.ceil(maxHP / allAttack);
+      int singleOnlyCount = 0;
+
+      for (int monsterNo : monstersHPList) {
+        // doubleがないと、1/10のようなときに正しく動かない
+        singleOnlyCount += (int) Math
+            .ceil((double) monstersHPList.get(monsterNo) / (double) singleAttack);
+      }
+
+      if (allOnlyCount <= singleOnlyCount) {
+        // 全体攻撃
+        monstersHPList.replaceAll(hp -> hp - allAttack);
+      } else {
+        // 最大HPの敵に単体攻撃
+        monstersHPList.set(maxHPIndex, maxHP - singleAttack);
+      }
+
+      count++;
+      // 敵がいなくなるまで続けるため
+      monstersHPList.removeIf(hp -> hp <= 0);
+    }
+
+    return count;
+  }
+
+}