# -*- coding: utf-8 -*-
"""
No.164 ちっちゃくないよ！！
https://yukicoder.me/problems/no/164

"""
import sys
from sys import stdin
input = stdin.readline


def solve(V):
    ans = float('inf')
    for v in V:
        v = v.lstrip('0')
        for x in range(2, 36+1):
            try:
                t = int(v, x)
                ans = min(ans, t)
                break
            except ValueError:
                pass
    return ans


def main(args):
    N = int(input())
    V = [input().strip() for _ in range(N)]
    ans = solve(V)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])