#include<vector>
#include<map>
#include<set>
#include<queue>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cctype>
#include<string>
#include<bitset>
#include<cstring>
#include<list>
using namespace std;
typedef vector<int>VI;
typedef vector<VI>VVI;
typedef vector<string>VS;
typedef pair<int,int>PII;
typedef long long LL;
typedef pair<LL,LL>PLL;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define PB push_back
#define EACH(i,c) for(typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define F first
#define S second

int main(){
    LL mi=100000000000000000;
    int n;
    cin>>n;
    while(n--){
        string str;
        cin>>str;
        LL d=0;
        REP(i,str.length()){
            d*=36;
            LL v=(isdigit(str[i])?str[i]-'0':str[i]-'A'+10);
            d+=v;
        }
        mi=min(mi,d);
    }
    cout<<mi<<endl;
    return 0;
}