dig = {}
for i in range(10):
    dig[str(i)] = i
for i in range(26):
    dig[chr(i+65)] = i + 10
N = int(input())
ans = 1<<64
for _ in range(N):
    V = input()[::-1]
    l = 0
    for v in V:
        l = max(l, dig[v])
    l += 1
    s = 0
    for i,v in enumerate(V):
        s += pow(l, i) * dig[v]
    ans = min(ans, s)
print(ans)