#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
 
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define CLR(a) memset((a), 0 ,sizeof(a))
#define MCLR(a) memset((a), -1 ,sizeof(a))
#define SZ(a) (sizeof(a))
#define FILL(a,v) fill((int*)a,(int*)(a+(SZ(a)/SZ(*(a)))),v)

bool cheak(int x,int y,int xMax,int yMax)
{return x >= 0 && y >= 0 && xMax > x && yMax > y;}
const int dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;
typedef long long ll;
typedef unsigned long long ull;
const ull INF = 18446744073709551615;

ull cast(string s)
{

	int len = s.length();
	
	int Max = 0;
	REP(i,len)
	{
		if(s[i] >= '0' && s[i] <= '9')
		{
			Max = max(Max,s[i]-'0'+1);
		}else
		{
			Max = max(Max,s[i]-'A'+11);
		}
	}
	

	ull sum = 0;

	REP(i,len)
	{
		ull tmp;
		if(i == len-1)
		tmp = 1;
		else
		tmp = Max;
		if(s[i] >= '0' && s[i] <= '9')
		sum = tmp*(sum+(s[i]-'0'));
		else
		sum = tmp*(sum+(s[i]-'A'+10));
	}


	return sum;
}

int main()
{
	int n;
	cin >> n;
	
	ull Min = INF;
	REP(i,n)
	{
		string v;
		cin >> v;
		Min = min(cast(v),Min);
	}

	cout << Min << endl;
	return 0;
}