diff --git a/include/bmath/bmath.hh b/include/bmath/bmath.hh
index 8c1b6d3..b297b6b 100644
--- a/include/bmath/bmath.hh
+++ b/include/bmath/bmath.hh
@@ -2,5 +2,6 @@
 #define BMATH_BMATH_HH
 
 #include "bmath/mint.hh"
+#include "bmath/sieve.hh"
 
 #endif
diff --git a/include/bmath/mint.hh b/include/bmath/mint.hh
index da50055..12356af 100644
--- a/include/bmath/mint.hh
+++ b/include/bmath/mint.hh
@@ -1,14 +1,14 @@
 #ifndef BMATH_MINT_HH
 #define BMATH_MINT_HH
 
-namespace bmath {
-
 #include <format>
 #include <iterator>
 #include <ostream>
 #include <stdexcept>
 #include <string>
 
+namespace bmath {
+
 inline constexpr uint64_t DEFAULT_MOD = 1'000'000'007;
 
 template <std::integral T, T M = static_cast<T>(DEFAULT_MOD)>
diff --git a/include/bmath/sieve.hh b/include/bmath/sieve.hh
new file mode 100644
index 0000000..a0db78f
--- /dev/null
+++ b/include/bmath/sieve.hh
@@ -0,0 +1,6 @@
+#ifndef BMATH_SIEVE_HH
+#define BMATH_SIEVE_HH
+
+namespace bmath {};
+
+#endif