n = int(input())
L = [list(input()) for _ in range(n)]

ans = 10**18
for i in range(n):
    res = 0
    m = len(L[i])
    max_ = '0'
    for j in range(m):
        if L[i][j].isdigit():
            if max_.isdigit():
                max_ = max(max_, L[i][j])
        else:
            if max_.isdigit():
                max_ = L[i][j]
            else:
                max_ = max(max_, L[i][j])
    if max_.isdigit():
        d = int(max_) + 1
    else:
        d = ord(max_) - ord('A') + 11
    for j in range(m):
        if L[i][j].isdigit():
            res += pow(d, m - j - 1) * int(L[i][j])
        else:
            res += pow(d, m - j - 1) * (ord(L[i][j]) - ord('A') + 10)
    ans = min(ans, res)
print(ans)