def f(c):
    if '0'<=c<='9':
        return int(c)
    else:
        return ord(c)-ord('A')+10

ans = float('inf')

for _ in range(int(input())):
    S = input()
    k = max(f(c) for c in S)+1
    v = 0
    
    for i, c in enumerate(S[::-1]):
        v += f(c)*pow(k, i)
    
    ans = min(ans, v)

print(ans)