N = int(input())
ans = 10**20
for i in range(N):
    V = list(input())
    L = [0]*len(V)
    for j in range(len(L)):
        if '0' <= V[j] <= '9':
            L[j]=int(V[j])
        else:
            L[j]=ord(V[j])-65+10
    n = max(L)+1
    temp = 0
    L = L[::-1]
    for j in range(len(L)):
        temp+=L[j]*n**j
    ans = min(temp,ans)
print(ans)