#include <bits/stdc++.h>
using namespace std;
int main(void){
    long long ans=5000000000000000000;
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        string s;
        cin>>s;
        int minn=2;
        for(int j=0;j<s.size();j++){
            if('1'<s[j]&&s[j]<='9'){
                minn=max(minn,s[j]-'0'+1);
            }else if('A'<=s[j]&&s[j]<='Z'){
                minn=max(minn,s[j]-'A'+11);
            }
        }
        long long tmp=0;
        for(int j=0;j<s.size();j++){
            tmp*=minn;
            tmp+=(s[j]<='9'?s[j]-'0':s[j]-'A'+10);
        }
        //cout<<minn<<" "<<tmp<<endl;
        ans=min(tmp,ans);
    }
    cout<<ans<<endl;
    return 0;
}