#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<numeric>
#include<functional>
#include<complex>

using namespace std;
#define BET(a,b,c) ((a)<=(b)&&(b)<(c))
#define FOR(i,n) for(int i=0,i##_end=(int(n));i<i##_end;i++)
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(),(x).end()
#define MP make_pair
#define FOR_EACH(it,v) for(__typeof(v.begin()) it=v.begin(),it_end=v.end() ; it != it_end ; it++)
typedef vector<int> VI;
typedef vector<VI> VVI;

int tonumber(char c){
    if(isdigit(c)) return c - '0';
    return c - 'A' + 10;
}

int main()
{
    int n;
    cin>>n;
    unsigned long long ans = 1ULL<<63 ;
    FOR(i,n){
        string s;
        cin>>s;
        int maxNumber = 0;
        FOR(j,SZ(s)) maxNumber = max(maxNumber, tonumber(s[j]));
        unsigned long long val = 0;
        FOR(j,SZ(s)){
            val = val * (maxNumber + 1) + tonumber(s[j]);
        }
        if(ans > val) ans = val;
    }
    cout<<ans<<endl;
    return 0;
}