import sys

sys.setrecursionlimit(10 ** 6)
stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().strip()
ntp = lambda: tuple(map(int, stdin.readline().split()))
mod = 10 * 9 + 7
inf = 2 << 60

num = inf

n = ni()

for _ in range(n):
    S = ns()
    T = list(reversed(list(S)))
    m = 0
    for i in range(len(S)):
        j = ord(T[i]) - 48
        m += j * (32 ** i)

    if m < num:
        num = m

print(num)