D = {str(n):n for n in range(10)}
for i in range(65,91):
    D[chr(i)] = i-55
N = int(input())
ans = 36**12
for _ in range(N):
    v = input().strip()
    a = max(v)
    base = D[a]+1
    num = 0
    k = len(v)
    for i in range(k):
        num += D[v[i]]*pow(base,k-i-1)
    ans = min(ans,num)
print(ans)