import itertools
from typing import Dict, Any


class SolutionBase:
    # internal code for
    @staticmethod
    def read_int():
        return int(input())

    @staticmethod
    def read_ints():
        return [int(i) for i in input().split()]

    @staticmethod
    def read_line():
        return input().strip()

    # implementation in subclass
    def load_data(self) -> Dict[str, Any]:
        raise NotImplementedError

    def solve(self, **kwargs):
        raise NotImplementedError

    def format_answer(self, answer) -> str:
        raise NotImplementedError

    def main(self):
        t = self.read_int()
        for i in range(1, t+1):
            answer = self.format_answer(
                self.solve(
                    **self.load_data()
                )
            )
            print(f"Case #{i}: {answer}")


class MySolution(SolutionBase):
    def load_data(self) -> Dict[str, Any]:
        index = self.read_int()
        return {'index': index}

    def get_first_for(self, index):
        left = 0
        right = 10 ** 7
        while left + 1 < right:
            middle = (left + right) // 2
            middle_count = self.get_total_count(middle)
            if middle_count < index:
                left = middle
            else:
                right = middle
        return right

    def get_total_count(self, i):
        return 13 * i * (i + 1)

    def solve(self, index):
        limit = self.get_first_for(index)
        index -= self.get_total_count(limit-1)
        return (index - 1) // limit

    def format_answer(self, answer) -> str:
        return chr(ord('A') + answer)


if __name__ == "__main__":
    MySolution().main()