diff --git a/C279991/.tutorial.md b/C279991/.tutorial.md
index e7f36ef..680ec02 100644
--- a/C279991/.tutorial.md
+++ b/C279991/.tutorial.md
@@ -57,3 +57,9 @@ multiset.upper_bound()
 ### M - Alice and Bob
 
 multiset搞一下（又忘记clear了）
+
+### N - Moo University - Financial Aid
+
+按成绩排序后用两个堆分别维护每头牛前后花钱最少的`n/2`头牛，逆序扫一遍即可。
+
+> 辣鸡poj不让用`bits/stdc++.h`
diff --git a/C279991/CMakeLists.txt b/C279991/CMakeLists.txt
index 3daa99d..34e3b5c 100644
--- a/C279991/CMakeLists.txt
+++ b/C279991/CMakeLists.txt
@@ -2,9 +2,9 @@
 cmake_minimum_required(VERSION 3.0)
 set(CMAKE_CXX_STANDARD 17)
 if(MSVC)
-    add_compile_options("/Zc:__cplusplus")
+    add_compile_options("/Zc:__cplusplus" "/wd6031")
 endif()
-include_directories("C:\\Programs\\GCC\\x86_64-8.1.0-release-posix-seh-rt_v6-rev0\\lib\\gcc\\x86_64-w64-mingw32\\8.1.0\\include\\c++\\x86_64-w64-mingw32")
+include_directories("C:\\Users\\Administrator\\AppData\\Local\\Programs\\MSYS2\\mingw64\\include\\c++\\8.2.1\\x86_64-w64-mingw32")
 add_executable(A A.cpp)
 add_executable(B B.cpp)
 add_executable(C C.cpp)
diff --git a/C279991/N.cpp b/C279991/N.cpp
index 7c92ea4..30ba0d5 100644
--- a/C279991/N.cpp
+++ b/C279991/N.cpp
@@ -1,8 +1,46 @@
 #define _CRT_SECURE_NO_WARNINGS
 #define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
-#include <bits/stdc++.h>
+//#include <bits/stdc++.h>
+#include <algorithm>
+#include <cstdio>
+#include <queue>
+#include <utility>
 using namespace std;
+const int N = 1e5 + 50;
+pair<int, int> a[N];
+int b[N];
 int main()
 {
+    int n, c, f;
+    scanf("%d%d%d", &n, &c, &f);
+    for (int i = 0; i < c; i++)
+        scanf("%d%d", &a[i].first, &a[i].second);
+    sort(a, a + c);
+    priority_queue<int> h1, h2;
+    for (int i = 0, x = 0; i < c; i++)
+    {
+        if (i >= (n >> 1))
+        {
+            b[i] += x;
+            if (a[i].second >= h1.top()) continue;
+            x -= h1.top(), h1.pop();
+        }
+        x += a[i].second, h1.push(a[i].second);
+    }
+    for (int i = c - 1, x = 0; i >= 0; i--)
+    {
+        if ((c - i - 1) >= (n >> 1))
+        {
+            b[i] += x;
+            if (a[i].second >= h2.top()) continue;
+            x -= h2.top(), h2.pop();
+        }
+        x += a[i].second, h2.push(a[i].second);
+    }
+    int ans = -1;
+    for (int i = c - 1 - (n >> 1); i >= (n >> 1) && ans == -1; i--)
+        if (b[i] + a[i].second <= f)
+            ans = a[i].first;
+    printf("%d", ans);
     return 0;
-}
+}
\ No newline at end of file