Problem: Olesya loves numbers consisting of n digits, and Rodion only likes numbers that are divisible by t. Find some number that satisfies both of them.

Your task is: given the n and t print an integer strictly larger than zero consisting of n digits that is divisible by t. If such number doesn't exist, print  - 1.

Input

The single line contains two numbers, n and t (1 ≤ n ≤ 100, 2 ≤ t ≤ 10) — the length of the number and the number it should be divisible by.

Output

Print one such positive number without leading zeroes, — the answer to the problem, or  - 1, if such number doesn't exist. If there are multiple possible answers, you are allowed to print any of them.

Examples

Input

3 2


Output

712

Solution (in PYTHON3):

Solution:
class CodeforcesTask584ASolution:
    def __init__(self):
        self.result = ''
        self.n_t = []

    def read_input(self):
        self.n_t = [int(x) for x in input().split(" ")]

    def process_task(self):
        if len(str(self.n_t[1])) > self.n_t[0]:
            self.result = "-1"
        else:
            res = 10 ** (self.n_t[0] - 1) if self.n_t[1] == 10 else self.n_t[1] * (10 ** (self.n_t[0] - 1))
            self.result = str(res)

    def get_result(self):
        return self.result


if __name__ == "__main__":
    Solution = CodeforcesTask584ASolution()
    Solution.read_input()
    Solution.process_task()
    print(Solution.get_result())