diff --git a/sitou/src/B147_slime.java b/sitou/src/B147_slime.java
new file mode 100644
index 0000000000000000000000000000000000000000..b84b2885ef525802f2c3421bf5ce75511e62ea54
--- /dev/null
+++ b/sitou/src/B147_slime.java
@@ -0,0 +1,55 @@
+package src;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Scanner;
+
+public class B147_slime {
+  static final int FAILED = -1;
+  
+  public static void main(String[] args) {
+    final Scanner sc = new Scanner(System.in);
+    final int slimeNum = sc.nextInt();
+    final int mySize = sc.nextInt();
+    ArrayList<Integer> slimesSizeList = new ArrayList<>();
+    for (int i = 0; i < slimeNum; i++) {
+      slimesSizeList.add(sc.nextInt());
+    }
+
+    final int count = mergeSlimes(mySize, slimesSizeList);
+    System.out.println(count);
+    sc.close();
+  }
+
+  private static int mergeSlimes(final int mySize, final ArrayList<Integer> slimesSizeList) {
+    int count = 0;
+
+    int nowMySize = mySize;
+    ArrayList<Integer> nowSlimesSizeList = new ArrayList<>(slimesSizeList);
+    Collections.sort(nowSlimesSizeList, Collections.reverseOrder()); // サイズが大きいものから順に比較するため
+
+    while (!nowSlimesSizeList.isEmpty() && nowMySize <= nowSlimesSizeList.get(0)) { // 自分が最大サイズになったら終わり
+      int mergedIndex = findMergableSlime(nowMySize, nowSlimesSizeList);
+
+      if (mergedIndex != FAILED) {
+        nowMySize += nowSlimesSizeList.get(mergedIndex);
+        nowSlimesSizeList.remove(mergedIndex);
+        count++;
+      } else {
+        count = FAILED;
+        break;
+      }
+    }
+
+    return count;
+  }
+
+  private static int findMergableSlime(final int nowMySize, final ArrayList<Integer> nowSlimesSizeList) {
+    for (int i = 0; i < nowSlimesSizeList.size(); i++) { // sizeが可変だと拡張forはできない? + スライムのsizeとリストの.sizeが紛らわしい?
+      if (nowMySize >= nowSlimesSizeList.get(i)) {
+        return i;
+      }
+    }
+    return FAILED;
+  }
+}