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

ans = ''
num = inf

n = ni()

for _ in range(n):
    S = ns()
    T = list(reversed(list(S)))
    m = 0
    mx = 0
    for i in range(len(S)):
        if ord(T[i]) > 57:
            j = ord(T[i]) - 55
        else:
            j = int(T[i])
        m += j * (36 ** i)
        if mx < j:
            mx = j

    if m < num:
        ans = T
        num = m
        ansmx = mx + 1

m = 0
for i in range(len(ans)):
    if ord(ans[i]) > 57:
        j = ord(ans[i]) - 55
    else:
        j = int(ans[i])
    m += j * (ansmx ** i)
print(m)