N = int(input())

todec = {chr(ord("A") + i): 10 + i for i in range(26)}
for i in range(10):
    todec[str(i)] = i
V = [input() for i in range(N)]

ans = 10 ** 20
for i in range(N):
    val = 0
    base = 0
    for j in range(len(V[i])):
        base = max(base, todec[V[i][j]])
    base += 1
    for j in range(len(V[i])):
        val *= base
        val += todec[V[i][j]]
    ans = min(ans, val)
print(ans)