#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long int ll;

int search(string s){
	int ans=0;
	for(int i=0;i<(int)s.size();i++){
		if('0'<=s[i]&&s[i]<='9')	ans=max(ans,(int)s[i]-'0');
		else 	ans=max(ans,(int)s[i]-'A'+10);
	}
	return ans+1;
}

ll change(string s,int size){
	ll ans=0;
	for(int i=0;i<(int)s.size();i++){
		ans*=size;
		if('0'<=s[i]&&s[i]<='9')	ans+=(int)s[i]-'0';
		else 	ans+=(int)s[i]-'A'+10;
	}
	return ans;
}

int main(){
	int n;	cin>>n;
	ll ans=ULLONG_MAX;
	for(int i=0;i<n;i++){
		string v;	cin>>v;
		ans=min(ans,change(v,search(v)));
	}
	cout<<ans<<endl;
	return 0;
}