diff --git a/src/list.h b/src/list.h
index 5e45018..b0bead8 100644
--- a/src/list.h
+++ b/src/list.h
@@ -2,13 +2,15 @@
 #include <gmp.h>
 #include <stdbool.h>
 
+#include "types.h"
+
 /**
  * @brief An infinitely expanding list type.
  */
 typedef struct {
 	mpz_t *list; //!< The list of elements
-	unsigned long long int size; //!< How many elements are in the list
-	unsigned long long int end; //!< The last element of the list (in use)
+	ulli size; //!< How many elements are in the list
+	ulli end; //!< The last element of the list (in use)
 } List;
 
 /**
diff --git a/src/main.c b/src/main.c
index 44a5555..ed056d0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -5,6 +5,7 @@
 #include <gmp.h>
 
 #include "list.h"
+#include "types.h"
 #include "optimizers.h"
 
 static bool run;
@@ -37,7 +38,7 @@ int main(void) {
 
 	do {
 		// Loop through found primes
-		for(unsigned long long int i = 0; i < primes.size; ++i) {
+		for(ulli i = 0; i < primes.size; ++i) {
 			// If `num' is divisible by a prime then go to the next number
 			if(mpz_divisible_p(num, primes.list[i]) != 0) goto nextPrime;
 		}
diff --git a/src/types.h b/src/types.h
new file mode 100644
index 0000000..9de6f13
--- /dev/null
+++ b/src/types.h
@@ -0,0 +1,2 @@
+#pragma once
+typedef unsigned long long int ulli;