diff --git a/2019/22.cpp b/2019/22.cpp
index 6faae77..de4f07a 100644
--- a/2019/22.cpp
+++ b/2019/22.cpp
@@ -4,9 +4,9 @@
 #include <variant>
 #include <vector>
 
-#include <gmpxx.h>
-
 #include <aocpp/Startup.hpp>
+#include <zmod.hpp>
+using namespace zmod;
 using namespace aocpp;
 
 template <class... Ts> struct overloaded : Ts... { using Ts::operator()...; };
@@ -14,45 +14,6 @@ template <class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
 
 namespace {
 
-template <unsigned long Mod>
-class ZMod {
-  mpz_class value;
-
-public:
-  ZMod() : value {} {}
-  ZMod(long value) : ZMod{mpz_class{value}} {}
-  ZMod(mpz_class value) {
-    mpz_mod_ui(this->value.get_mpz_t(), value.get_mpz_t(), Mod);
-  }
-
-  auto operator+(ZMod const& rhs) const -> ZMod {
-    return {value + rhs.value};
-  }
-
-  auto operator-() const -> ZMod {
-    return {-value};
-  }
-
-  auto operator-(ZMod const& rhs) const -> ZMod {
-    return {value - rhs.value};
-  }
-
-  auto operator*(ZMod const& rhs) const -> ZMod {
-    return {value * rhs.value};
-  }
-
-  auto inverse() const -> ZMod {
-    mpz_class m{Mod};
-    ZMod result;
-    mpz_invert(result.value.get_mpz_t(), value.get_mpz_t(), m.get_mpz_t());
-    return result;
-  }
-
-  auto friend operator<<(std::ostream & out, ZMod<Mod> const& x) -> std::ostream & {
-  return out << x.value.get_ui();
-}
-};
-
 template <typename Rep>
 struct LinearFunction {
   Rep scale;
diff --git a/2019/CMakeLists.txt b/2019/CMakeLists.txt
index 6a34a30..f67ede9 100644
--- a/2019/CMakeLists.txt
+++ b/2019/CMakeLists.txt
@@ -50,7 +50,7 @@ add_executable(20 20.cpp)
 target_link_libraries(20 aocpp)
 
 add_executable(22 22.cpp)
-target_link_libraries(22 aocpp PkgConfig::GMP)
+target_link_libraries(22 aocpp zmod)
 
 add_executable(23 23.cpp)
 target_link_libraries(23 aocpp intcode)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 071ae73..5c33833 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,5 +18,6 @@ find_package(PkgConfig)
 pkg_check_modules(GMP REQUIRED IMPORTED_TARGET gmp)
 
 add_subdirectory(lib)
+add_subdirectory(zmod)
 add_subdirectory(intcode)
 add_subdirectory(2019)
diff --git a/zmod/CMakeLists.txt b/zmod/CMakeLists.txt
new file mode 100644
index 0000000..faabdd4
--- /dev/null
+++ b/zmod/CMakeLists.txt
@@ -0,0 +1,3 @@
+add_library(zmod INTERFACE)
+target_link_libraries(zmod PkgConfig::GMP)
+target_include_directories(zmod PUBLIC include)
\ No newline at end of file
diff --git a/zmod/include/zmod.hpp b/zmod/include/zmod.hpp
new file mode 100644
index 0000000..b784e9d
--- /dev/null
+++ b/zmod/include/zmod.hpp
@@ -0,0 +1,50 @@
+#ifndef ZMOD_HPP_
+#define ZMOD_HPP_
+
+#include <iostream>
+#include <gmpxx.h>
+
+namespace zmod {
+
+template <unsigned long Mod>
+class ZMod {
+  mpz_class value;
+
+public:
+  ZMod() : value {} {}
+  ZMod(long value) : ZMod{mpz_class{value}} {}
+  ZMod(mpz_class value) {
+    mpz_mod_ui(this->value.get_mpz_t(), value.get_mpz_t(), Mod);
+  }
+
+  auto operator+(ZMod const& rhs) const -> ZMod {
+    return {value + rhs.value};
+  }
+
+  auto operator-() const -> ZMod {
+    return {-value};
+  }
+
+  auto operator-(ZMod const& rhs) const -> ZMod {
+    return {value - rhs.value};
+  }
+
+  auto operator*(ZMod const& rhs) const -> ZMod {
+    return {value * rhs.value};
+  }
+
+  auto inverse() const -> ZMod {
+    mpz_class m{Mod};
+    ZMod result;
+    mpz_invert(result.value.get_mpz_t(), value.get_mpz_t(), m.get_mpz_t());
+    return result;
+  }
+
+  auto friend operator<<(std::ostream & out, ZMod<Mod> const& x) -> std::ostream & {
+    return out << x.value.get_ui();
+  }
+};
+
+}
+
+#endif
\ No newline at end of file
diff --git a/zmod/src/zmod.cpp b/zmod/src/zmod.cpp
new file mode 100644
index 0000000..2ece585
--- /dev/null
+++ b/zmod/src/zmod.cpp
@@ -0,0 +1 @@
+#include <zmod.hpp>