#include<iostream>
using namespace std;
int b;
string d;
main()
{
	cin>>b>>d;
	int x;
	for(x=1;x<d.size();x++)
	{
		int sub=x*(b-1);
		int id=d.size()-x;
		while(sub>0&&id>=0)
		{
			if(d[id]-48>=sub%b)
			{
				d[id]-=sub%b;
			}
			else
			{
				d[id]=d[id]-sub%b+b;
				sub+=b;
			}
			sub/=b;
			id--;
		}
		if(sub>0)
		{
			for(int i=0;i<=d.size()-x;i++)sub*=b;
			sub-=x*(b-1);
			int id=d.size()-x;
			while(sub>0)
			{
				if(d[id]-48>=sub%b)d[id]-=sub%b;
				else
				{
					d[id]=d[id]-sub%b+b;
					sub+=b;
				}
				sub/=b;
				id--;
			}
			break;
		}
	}
	string ans="";
	int carry=0;
	for(int i=0;i<d.size()-x;i++)carry=carry*b+d[i]-48;
	for(int i=x;i>0;i--)
	{
		carry=carry*b+d[d.size()-i]-48;
		ans+=48+carry/x+(i==x);
		int t=carry/x+(i==x);
		if(t<0||t>9)return 1;
		carry%=x;
	}
	if(carry>0)
	{
		int id=ans.size()-1;
		while(ans[id]-48==b-1)ans[id--]=48;
		ans[id]++;
	}
	else
	{
		int id=ans.size()-1;
		while(ans[id]-48==0)ans[id--]=48+b-1;
		ans[id]--;
	}
	cout<<ans[carry?carry-1:ans.size()-1]<<endl;
}