diff --git a/Cargo.toml b/Cargo.toml
index 2c21c52..72955be 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,6 +3,7 @@ name = "highpymath"
 version = "0.1.1"
 edition = "2021"
 license = "MIT"
+authors = ["pyrootcpp"]
 description = "High Quality Rust Python Module"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
diff --git a/highpymath/__init__.py b/highpymath/__init__.py
index 9c485b0..f16820a 100644
--- a/highpymath/__init__.py
+++ b/highpymath/__init__.py
@@ -435,7 +435,7 @@ def calc_pi(return_int: bool = False, return_string: bool = False):
 
 pi = calc_pi()
 
-def calc_e(max: int = 1000, return_int: bool = True, return_string: bool = False):
+def calc_e(max: int = 10, return_int: bool = True, return_string: bool = False):
     """
     Calculate the euler number.
     """
diff --git a/highpymath/math.pyx b/highpymath/math.pyx
new file mode 100644
index 0000000..e69de29
diff --git a/setup.py b/setup.py
new file mode 100644
index 0000000..acca09c
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,22 @@
+# setup.py
+from setuptools import setup, Extension, find_packages
+from setuptools_rust import RustExtension
+from Cython.Build import cythonize
+
+def read(file):
+    with open(file, 'r') as f:
+        return f.read()
+
+setup(
+    name="highpymath",
+    version="0.1.1",
+    packages=find_packages(),
+    description="High Quality Math library for Python",
+    author="pyrootcpp",
+    author_email="pyrootcpp@outlook.de",
+    long_description=read('README.rst'),
+    license=read('LICENSE'),
+    rust_extensions=[RustExtension("highpymath", "Cargo.toml", binding="pyo3")],
+    ext_modules=cythonize("highpymath/math.pyx"),
+    zip_safe=False,
+)
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 272a464..2719b5a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -174,24 +174,11 @@ fn calc_pi() -> PyResult<PyFloat> {
     Ok(_pi)
 }
 
-fn facto(n: PyUInt) -> PyUInt {
-    let mut result = 1;
-    for i in 1..=n {
-        let new_result = result * i;
-        if new_result < result {  // Überlaufprüfung
-            panic!("Integer overflow during factorial calculation");
-        }
-        result = new_result;
-    }
-    result
-}
-
 #[pyfunction]
-fn calc_e(max: PyInt) -> PyResult<PyFloat> {
-    let mut result: PyFloat = 0.0;
+fn calc_e(max: PyInt) -> PyResult<PyInt> {
+    let mut result: PyInt = 0;
     for i in 0..max {
-        let factorial_result = facto(i as PyUInt);  // Typkonvertierung, falls notwendig
-        result += 1.0 / factorial_result as PyFloat;  // Korrekte Typumwandlung
+        result += result.checked_mul(i).unwrap();
     }
     Ok(result)
 }