def code(c):
    if (c.isdigit()):
        return ord(c) - ord('0')
    else:
        return ord(c) - ord('A') + 10


def main():
    n = int(input())

    ans = 10**50
    for _ in range(n):
        s = input()
        b = max([code(c) for c in s]) + 1

        x = 0
        for c in s:
            x = x * b + code(c)

        ans = min(ans, x)

    print(ans)


if __name__ == "__main__":
    main()