#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
typedef complex<ld> Point;
const ld eps = 1e-11;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
typedef pair<ld, ld> LDP;
typedef unsigned long long ul;
int b;
string minu(string x, string y) {
	int len = x.length();
	int len2 = y.length();
	string res;
	rep1(i, len) {
		int t = x[len - i] - '0';
		if (len2 - i >= 0) {
			t -= y[len2 - i] - '0';
		}
		while (t < 0) {
			t += b; x[len - i - 1]--;
		}
		res.push_back('0' + t);
	}
	reverse(res.begin(), res.end()); 

	while (!res.empty() && res[0] == '0') {
		res.erase(res.begin());
	}
	return res;
}
string make(int n) {
	string res;
	if (n == 0)return "0";
	else if (n == 1) {
		res.push_back('0' + b - 1); return res;
	}
	else {
		int c = n - 1;
		while (c) {
			res.push_back('0' + (c%b));
			c /= b;
		}
		reverse(res.begin(), res.end());
		rep(i, n - 1) {
			res.push_back('0' + b - 2);
		}
		res.push_back('0' + b - 1);
	}
	return res;
}
bool great(string x, string y) {
	if (x.length() != y.length()) {
		return x.length() > y.length();
	}
	return x >= y;
}
pair<string, int> q(string x, int d) {
	int len = x.length();
	string res;
	int c = 0;
	rep(i, len) {
		c += x[i] - '0';
		res.push_back('0' + (c / d)); c %= d;
		c *= b;
	}
	while (!res.empty() && res[0] == '0') {
		res.erase(res.begin());
	}
	return { res,c / b };
}
string make_base(int n) {
	string res;
	res.push_back('1');
	rep(i, n - 1) {
		res.push_back('0');
	}
	return res;
}
string add(string a, string y) {
	reverse(a.begin(), a.end());
	reverse(y.begin(), y.end());
	int len = max(a.length(), y.length());
	int rest = 0; string res;
	rep(i, len + 1) {
		if (i < (int)a.length()) {
			rest += a[i] - '0';
		}
		if (i < (int)y.length()) {
			rest += y[i] - '0';
		}
		res.push_back('0' + (rest % b));
		rest /= b;
	}
	while (res.length() && res[res.length() - 1] == '0')res.erase(res.end() - 1);
	reverse(res.begin(), res.end());
	return res;
}

int main() {
	cin >> b;
	string s; cin >> s;
	int le = 0, ri = 100001;
	while (ri - le > 1) {
		int mid = (ri + le) >> 1;
		string nex = make(mid);
		if (great(nex, s))ri = mid;
		else le = mid;
	}
	//cout << ri << endl;
	//cout << s << endl;
	//cout << make(ri - 1) << endl;
	s = minu(s, make(ri - 1));
	//cout << s << endl;
	pair<string, int> ans = q(s, ri);
	//cout << ans.first << endl;
	ans.first = add(ans.first, make_base(ri));
	//cout << ans.first << endl;
	//cout << ans.second << endl;
	if (ans.second > 0) {
		cout << ans.first[ans.second-1] << endl;
	}
	else {
		ans.first = minu(ans.first, "1");
		cout << ans.first[ri - 1] << endl;
	}
	return 0;
}