diff --git a/202508/326 isPowerOfThree/C#/Program.cs b/202508/326 isPowerOfThree/C#/Program.cs
new file mode 100644
index 0000000..a522990
--- /dev/null
+++ b/202508/326 isPowerOfThree/C#/Program.cs	
@@ -0,0 +1,21 @@
+public class Solution {
+    public bool IsPowerOfThree(int n) {
+        if(n <= 0)
+            return false;
+        if(n == 1)
+            return true;
+        if(n % 3 != 0)
+            return false;
+        return IsPowerOfThree(n/3);
+    }
+}
+
+class program{
+    static void Main(){
+        var Solution = new Solution();
+
+        Console.WriteLine(Solution.IsPowerOfThree(9));
+        Console.WriteLine(Solution.IsPowerOfThree(0));
+        Console.WriteLine(Solution.IsPowerOfThree(-1));
+    }
+}
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diff --git a/202508/326 isPowerOfThree/C#/isPowerOfThree.csproj b/202508/326 isPowerOfThree/C#/isPowerOfThree.csproj
new file mode 100644
index 0000000..2150e37
--- /dev/null
+++ b/202508/326 isPowerOfThree/C#/isPowerOfThree.csproj	
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>
diff --git a/202508/326 isPowerOfThree/description.md b/202508/326 isPowerOfThree/description.md
new file mode 100644
index 0000000..d4e511c
--- /dev/null
+++ b/202508/326 isPowerOfThree/description.md	
@@ -0,0 +1,22 @@
+Given an integer n, return true if it is a power of three. Otherwise, return false.
+
+An integer n is a power of three, if there exists an integer x such that n == 3x.
+
+ 
+
+Example 1:
+
+Input: n = 27
+Output: true
+Explanation: 27 = 33
+Example 2:
+
+Input: n = 0
+Output: false
+Explanation: There is no x where 3x = 0.
+Example 3:
+
+Input: n = -1
+Output: false
+Explanation: There is no x where 3x = (-1).
+ 
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