diff --git a/dohyeondol1/README.md b/dohyeondol1/README.md
index 26f1ff5..a674590 100644
--- a/dohyeondol1/README.md
+++ b/dohyeondol1/README.md
@@ -22,3 +22,5 @@
  | 18차시 | 2025.07.04 |  기하학  | [Water Testing](https://www.acmicpc.net/problem/16057)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/70|
  | 19차시 | 2025.07.09 |  그래프 이론  | [최소 스패닝 트리](https://www.acmicpc.net/problem/1197)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/76|
  | 20차시 | 2025.07.10 |  문자열  | [접두사](https://www.acmicpc.net/problem/1141)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/78|
+ | 21차시 | 2025.07.14 |  그래프 이론  | [석고 모형 만들기](https://www.acmicpc.net/problem/32031)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/81|
+ | 21차시 | 2025.07.19 |  그리디 알고리즘  | [대회 개최](https://www.acmicpc.net/problem/12915)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/87|
\ No newline at end of file
diff --git "a/dohyeondol1/\352\267\270\353\246\254\353\224\224 \354\225\214\352\263\240\353\246\254\354\246\230/22-dohyeondol1.cpp" "b/dohyeondol1/\352\267\270\353\246\254\353\224\224 \354\225\214\352\263\240\353\246\254\354\246\230/22-dohyeondol1.cpp"
new file mode 100644
index 0000000..dbb53db
--- /dev/null
+++ "b/dohyeondol1/\352\267\270\353\246\254\353\224\224 \354\225\214\352\263\240\353\246\254\354\246\230/22-dohyeondol1.cpp"	
@@ -0,0 +1,59 @@
+#include <iostream>
+using namespace std;
+
+int totalCompetiton;
+
+int main() {
+    int easy, easyMedium, medium, mediumHigh, high;
+    cin >> easy >> easyMedium >> medium >> mediumHigh >> high;
+    
+    while(true) {
+        bool easySubmitted = false;
+        bool mediumSubmitted = false;
+        bool highSubmitted = false;
+        
+        if(easy) {
+            easy--;
+            easySubmitted = true;
+        }
+        else {
+            if(easyMedium) {
+                easyMedium--;
+                easySubmitted = true;
+            }
+        }
+        
+        if(medium) {
+            medium--;
+            mediumSubmitted = true;
+        }
+        else {
+            if(easyMedium || mediumHigh) {
+                if(easyMedium >= mediumHigh)
+                    easyMedium--;
+                else
+                    mediumHigh--;
+                mediumSubmitted = true;
+            }
+        }
+        
+        if(high) {
+            high--;
+            highSubmitted = true;
+        }
+        else {
+            if(mediumHigh) {
+                mediumHigh--;
+                highSubmitted = true;
+            }
+        }
+        
+        if(!easySubmitted || !mediumSubmitted || !highSubmitted)
+            break;
+        
+        ++totalCompetiton;
+    }
+        
+    cout << totalCompetiton << '\n';
+    return 0;
+}
\ No newline at end of file