n = int(input())
min_val = float('inf')

for _ in range(n):
    s = input().strip()
    max_d = 0
    digits = []
    for c in s:
        if c.isdigit():
            d = int(c)
        else:
            d = ord(c) - ord('A') + 10
        digits.append(d)
        if d > max_d:
            max_d = d
    base = max_d + 1
    # Convert to decimal
    val = 0
    for d in digits:
        val = val * base + d
    if val < min_val:
        min_val = val

print(min_val)