I am unable to inculde the clojure.math.combinatorics namespace could someone help me.. i am beginner in clojure.

(ns clojure.core (:require [clojure.string :as str]) (:require [clojure.math.combinatorics :as combo]) (:gen-class))

(def test_cases (Integer/parseInt(read-line)))

(dotimes[r test_cases] (def l (str/split (read-line) #"\s+"))

(def n1 (Integer/parseInt(nth l 0))) (def n2 (Integer/parseInt(nth l 1)))

(println(combo/count-combinations n1 n2)))