#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<set>
#include<map>
#include<list>
#include<functional>
#include<cmath>
#include<climits>
#include<string>
#include<cstring>
using namespace std;
typedef unsigned long long ull;

int main(){
	int N;
	string S;
	cin>>N;
	ull ans = ULLONG_MAX;
	for(int i=0;i<N;i++){
		cin>>S;
		int n = 0;
		for(int j=0;j<S.size();j++){
			if(isalpha(S[j])) S[j] = S[j]-'A'+10;
			else S[j] -= '0';
			n = max(n,(int)S[j]);
		}
		n++;
		ull num = 0, w = 1;
		for(int j=S.size()-1; j>=0; j--, w*=n){
			num += S[j]*w;
		}
		ans = min(ans,num);
	}
	printf("%lld\n",ans);
	return 0;
}