diff --git a/problem/P1789/P1789.cpp b/problem/P1789/P1789.cpp
new file mode 100644
index 00000000..869e8946
--- /dev/null
+++ b/problem/P1789/P1789.cpp
@@ -0,0 +1,31 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int n, m, k, x, y, o, p, ans = 0;
+int dx1[13] = {2, 0, -2, 0, 1, 1, 1, 0, 0, 0, -1, -1, -1};
+int dy1[13] = {0, 2, 0, -2, 0, 1, -1, 1, 0, -1, 0, 1, -1};
+int dx2[25] = {-2, -2, -2, -2, -2, -1, -1, -1, -1, -1, 0, 0, 0,
+               0,  0,  1,  1,  1,  1,  1,  2,  2,  2,  2, 2};
+int dy2[25] = {-2, -1, 0,  1,  2, -2, -1, 0,  1,  2, -2, -1, 0,
+               1,  2,  -2, -1, 0, 1,  2,  -2, -1, 0, 1,  2};
+int main() {
+    cin >> n >> m >> k;
+    int a[n + 5][n + 5];
+    memset(a, 0, sizeof(a));
+    for (int i = 1; i <= m; i++) {
+        cin >> x >> y;
+        for (int j = 0; j < 13; j++)
+            a[x + dx1[j]][y + dy1[j]] = 1;
+    }
+    for (int i = 1; i <= k; i++) {
+        cin >> o >> p;
+        for (int j = 0; j < 25; j++)
+            a[o + dx2[j]][p + dy2[j]] = 1;
+    }
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= n; j++)
+            if (a[i][j] == 0)
+                ans++;
+    cout << ans;
+    return 0;
+}