#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <algorithm>
#include <cmath>

#include <string>
#include <list>
#include <queue>
#include <vector>
#include <complex>

/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) std::cout<<(p)<<std::endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

LL num[1000];
string s[1000];

LL cal(string s){//12文字
	int ke[12];
	int max = -1;
	for(unsigned int i=0;i<s.size();++i){
		if('0' <= s[i] && s[i] <= '9'){
			ke[i] = s[i] - '0';
		}else{
			ke[i] = s[i] - 'A' + 10;
		}
		if( max == -1 || max < ke[i]){
			max = ke[i];
		}
	}

	LL mul = 1;
	LL ans = 0;
	for(int i=(s.size()-1); i>=0 ; --i){
		ans += ke[i] * mul;
		mul *= (max+1);
	}
	return ans;
}

int main(void){
    std::cin.tie(0);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(6);//
	
	int N;
	cin>>N;
	rep(i,N){
		cin>>s[i];
	}
	rep(i,N){
		num[i] = cal(s[i]);
	}
	LL min = -1;
	rep(i,N){
		if( min == -1 || num[i] < min  ){
			min = num[i];
		}
	}
	P(min);
	return 0;
}