from collections import defaultdict, OrderedDict

class Node:

    __slots__ = 'key', 'val', 'cnt'

    def __init__(self, key, val, cnt=0):

        self.key, self.val, self.cnt = key, val, cnt

class LFUCache:

    def __init__(self, capacity):

        self.capacity = capacity

        self.cache = {}  # type {key: node}

        self.cnt2node = defaultdict(OrderedDict)

        self.mincnt = 0

    def get(self, key, default=-1):

        if key not in self.cache:

            return default

        node = self.cache[key]

        del self.cnt2node[node.cnt][key]

        if not self.cnt2node[node.cnt]:

            del self.cnt2node[node.cnt]

        node.cnt += 1

        self.cnt2node[node.cnt][key] = node

        if not self.cnt2node[self.mincnt]:

            self.mincnt += 1

        return node.val

    def put(self, key, value):

        if key in self.cache:

            self.cache[key].val = value

            self.get(key)

            return

        if len(self.cache) >= self.capacity:

            pop_key, _pop_node = self.cnt2node[self.mincnt].popitem(last=False)

            del self.cache[pop_key]

        self.cache[key] = self.cnt2node[1][key] = Node(key, value, 1)

        self.mincnt = 1

def test():

    c = LFUCache(2)

    c.put(1, 1)

    c.put(2, 2)

    assert c.get(1) == 1

    c.put(3, 3)

    assert c.get(2) == -1

    assert c.get(3) == 3

    c.put(4, 4)

    assert c.get(1) == -1

    assert c.get(3) == 3

    assert c.get(4) == 4

if __name__ == '__main__':

    test()