#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>
#include <queue>
#include <stack>

using namespace std;
 
const unsigned long long mod = 1000000000+7;

int main()
{
	unsigned long long res=0;
	unsigned long long tmp=1;

	for(int i=0;i<12;i++){
		res+=35*tmp;
		tmp*=36;
	}

	int n;
	cin>>n;

	for(int i=0;i<n;i++){
		string s;
		cin>>s;
		char cmax='0';
		for(int j=0;j<s.size();j++) cmax=max(cmax,s[j]);

		unsigned long long val=0;
		if(cmax<='9'){
			unsigned long long x=1;
			for(int j=s.size()-1;j>=0;j--){
				val+=(s[j]-'0')*x;
				x*=(cmax-'0'+1);
			}
		}else{
			unsigned long long x=1;
			for(int j=s.size()-1;j>=0;j--){
				if(s[j]<='9') val+=(s[j]-'0')*x;
				else val+=(s[j]-'A'+10)*x;
				x*=(cmax-'A'+1+10);
			}
		}
		res=min(res,val);
	}

	cout<<res<<endl;

	return 0;
}