--- /dev/null
+#if !defined(_choose_H)
+# define _choose_H (1)
+
+/*Computes the number of combinations of _n items, taken _m at a time without
+ overflow.
+ _n: The total number of items.
+ _b: The number taken at a time.
+ Return: The number of combinations of _n items taken _m at a time.*/
+unsigned choose(int _n,int _m);
+
+#endif