b = {}
for i in range(10):
    b[str(i)]=i
for i,alpha in enumerate(["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]):
    b[alpha]=i+10
    
V=[]
N=int(input())
for i in range(N):
    V.append(input())

def cal(v):
    temp=max([b[i] for i in v])+1
    sum=0
    count=0
    for i in reversed(range(len(v))):
        sum+=b[v[i]]*(temp**count)
        count+=1
    return sum

print(min([cal(v) for v in V]))