class Solution:
    def combine(self, n: int, k: int) -> List[List[int]]:
        rlt = []
        def comb(l, cur, k):
            if k == 0: 
                rlt.append(l) 
                return
            for i in range(cur, n + 1):
                tmp_l = l.copy()
                tmp_l.append(i)
                comb(tmp_l, i + 1, k - 1)
        comb([], 1, k)
        return rlt