ans = 36 ** 12 + 1

for _ in range(int(input())):
    S = [ord(i) - ord('0') if ord(i) < ord('A') else ord(i) - ord('A') + 10 for i in input()]
    p = max(S) + 1
    
    S.reverse()
    x = 0
    y = 1
    for s in S:
        x += s * y
        y *= p
    ans = min(ans, x)
    
print(ans)