CF758D.Ability To Convert

Alexander is learning how to convert numbers from the decimal system to any other, however, he doesn't know English letters, so he writes any number only as a decimal number, it means that instead of the letter A he will write the number 10. Thus, by converting the number 475 from decimal to hexadecimal system, he gets 11311 (475 = 1·162 + 13·161 + 11·160). Alexander lived calmly until he tried to convert the number back to the decimal number system.

Alexander remembers that he worked with little numbers so he asks to find the minimum decimal number so that by converting it to the system with the base n he will get the number k.

亚历山大正在学习如何将数字从十进制转换为任意其他进制，但他不认识英文字母，因此他仅用十进制数字来表示所有数——即，他用数字 10 代替字母 A。因此，将十进制数 475 转换为十六进制时，他得到的是 11311（因为 $475 = 1 \cdot 16^2 + 13 \cdot 16^1 + 11 \cdot 16^0$）。亚历山大一直平静地生活着，直到他尝试将该表示形式再转换回十进制数。

亚历山大记得自己当时处理的都是较小的数，因此他请求你找出满足如下条件的最小十进制数：将其转换为以 $n$ 为底的进制时，所得结果恰好为数字 $k$。

The first line contains the integer n (2 ≤ n ≤ 109). The second line contains the integer k (0 ≤ k < 1060), it is guaranteed that the number k contains no more than 60 symbols. All digits in the second line are strictly less than n.

Alexander guarantees that the answer exists and does not exceed 1018.

The number k doesn't contain leading zeros.

第一行包含整数 $n$（$2 \leq n \leq 10^9$）。第二行包含整数 $k$（$0 \leq k < 10^{60}$），保证数字 $k$ 的十进制表示长度不超过 60 位。第二行中所有数字均严格小于 $n$。

Alexander 保证答案存在，且不超过 $10^{18}$。

数字 $k$ 不含前导零。

Print the number x (0 ≤ x ≤ 1018) — the answer to the problem.

输出数字 x（0 ≤ x ≤ 10¹⁸）—— 本题的答案。

In the first example 12 could be obtained by converting two numbers to the system with base 13: 12 = 12·130 or 15 = 1·131 + 2·130.

在第一个例子中，12 可以通过将两个数转换为十三进制得到：$ 12 = 12 \cdot 13^0 $ 或 $ 15 = 1 \cdot 13^1 + 2 \cdot 13^0 $。