#include <iostream>
#include <algorithm>
using namespace std;
main(){
	int t;cin>>t;
	long long ans=-1;
	while(t--){
		string s;cin>>s;
		int mx=2;for(int i = 0; s.size() > i; i++)mx = max(mx,s[i]-(s[i]<='9'?47:54));
		long long z=0,q=1;
		reverse(s.begin(),s.end());
		for(int i=0;s.size()>i;i++)z+=q*(s[i]-(s[i]<='9'?48:55)),q*=mx;
		if(ans==-1)ans=z;
		else ans=min(ans,z);
	}
	cout << ans << endl;
}