#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    int n;
    cin >> n;
    ll ans = 0;
    rep(i,12){
        ans *= 36;
        ans += 35;
    }
    rep(_,n){
        string s;
        cin >> s;
        int m = s.size();
        ll ma = 0;
        rep(j,m) ma = max(ma, (ll)s[j]);
        if(ma <= '9') ma = ma - '0' + 1;
        else ma = ma - 'A' + 10 + 1;
        ll tmp = 0;
        rep(j,m){
            tmp *= ma;
            if(s[j] <= '9') tmp += s[j] - '0';
            else tmp += s[j] - 'A' + 10;
        }
        ans = min(ans, tmp);
    }

    cout << ans << endl;
    return 0;
}