#include <iostream>
#include <algorithm>
using namespace std;
int main(){
    int t;cin>>t;
    long long ans=-1;
    while(t--){
        string s;cin>>s;
        int mx=2;for(int i = 0; s.size() > i; i++)mx = max(mx,s[i]-('0'<=s[i]&&s[i]<='9'?47:54));
        long long z=0,q=1;
        reverse(s.begin(),s.end());
        for(int i=0;s.size()>i;i++)z+=q*(s[i]-('0'<=s[i]&&s[i]<='9'?48:55)),q*=mx;
        if(ans==-1)ans=z;
        else ans=min(ans,z);
    }
    cout << ans << endl;
}