diff --git a/sweet_geometry.c b/sweet_geometry.c
index afdfc35..efb461b 100644
--- a/sweet_geometry.c
+++ b/sweet_geometry.c
@@ -142,7 +142,13 @@ map_free (struct map * map)
 static struct item *
 map_get_item (struct map * map, unsigned int hash, unsigned int a, unsigned int b)
 {
-    struct item * item = map->items[hash % MAP_SIZE];
+    unsigned int tmp;
+    struct item * item;
+    tmp = a;
+    a = tmp > b ? tmp : b;
+    b = tmp > b ? b : tmp;
+
+    item = map->items[hash % MAP_SIZE];
     while (item != NULL && item->a != a && item->b != b) { item = item->next; }
     return item;
 }
@@ -158,8 +164,8 @@ map_add_item (struct map * map, unsigned int hash, unsigned int a, unsigned int
     item = malloc (sizeof (struct item));
     if (item == NULL) { return -1; }
 
-    item->a = a;
-    item->b = b;
+    item->a = a > b ? a : b;
+    item->b = a < b ? a : b;
     item->next = next;
     item->id = id;