diff --git a/src/BaekJoon/sa11k/1920/Main.java b/src/BaekJoon/sa11k/1920/Main.java
new file mode 100644
index 0000000..7d8c88d
--- /dev/null
+++ b/src/BaekJoon/sa11k/1920/Main.java
@@ -0,0 +1,51 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+    static int[] input;
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int inputNum = Integer.parseInt(br.readLine());
+        input = new int[inputNum];
+
+        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
+        for(int i = 0; i<inputNum; i++){
+            input[i] = Integer.parseInt(st.nextToken());
+        }
+
+        Arrays.sort(input);
+
+        int check = Integer.parseInt(br.readLine());
+        st = new StringTokenizer(br.readLine(), " ");
+
+        for(int i = 0; i<check; i++){
+            if(search(Integer.parseInt(st.nextToken())) >= 0)
+                System.out.println(1);
+            else
+                System.out.println(0);
+        }
+
+        br.close();
+    }
+
+    public static int search(int num){
+        int left = 0;
+        int right = input.length-1;
+
+        while(left<=right){
+            int mid = (left+right) / 2;
+
+            if(num < input[mid])
+                right = mid - 1;
+
+            else if(num > input[mid])
+                left = mid + 1;
+
+            else
+                return mid;
+        }
+
+        return -1;
+    }
+}
diff --git a/src/BaekJoon/sa11k/1929/Main.java b/src/BaekJoon/sa11k/1929/Main.java
new file mode 100644
index 0000000..126da05
--- /dev/null
+++ b/src/BaekJoon/sa11k/1929/Main.java
@@ -0,0 +1,34 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
+        StringBuilder sb = new StringBuilder();
+
+        int M = Integer.parseInt(st.nextToken());
+        int N = Integer.parseInt(st.nextToken());
+
+        for(int i = M; i<=N; i++){
+            if(checkPrime(i)){
+                sb.append(i).append("\n");
+            }
+        }
+
+        System.out.println(sb);
+        br.close();
+    }
+
+    public static boolean checkPrime(int num){
+        if(num<=1) return false;
+        else if(num==2) return true;
+        else{
+            for(int i = 2; i<=Math.sqrt(num); i++){
+                if((num % i) == 0) return false;
+            }
+            return true;
+        }
+    }
+}