N=int(raw_input())

def getNum(c):
    if ord(c) >= ord('0') and ord(c) <= ord('9'):
        return ord(c)-ord('0')
    return ord(c)-ord('A')+10

ans = 1e19

for i in range(N):
    s=raw_input()
    for b in range(2,37):
        tmp=0
        digit=1
        ok = True
        for c in s[::-1]:
            n=getNum(c)
            if n >= b:
                ok=False
                break
            tmp+=digit*n
            digit*=b
        if ok:
            ans=min(ans,tmp)
            break
print ans