#include <stdio.h>

const int len = 100100;
int B,D[len],F[len]; char S[len];

bool chk(int l)
{
	l--;
	for (int i=0;i<len;i++) F[i] = D[i];
	for (int i=0;i<l;i++) F[i] -= (B-1) * (i+1);
	for (int i=0;i<len;i++) if (F[i] < 0){
		if (i == len-1) return false;
		int g = (-F[i] + B-1) / B;
		F[i] += g * B;
		F[i+1] -= g;
	}
	return true;
}

int main()
{
	scanf ("%d %s",&B,S);

	{
		int l = 0;
		while (S[l]) l++;
		for (int j=0;j<l;j++) D[l-j-1] = S[j] - '0';
		D[0]--;
		for (int j=0;;j++){
			if (D[j] >= 0) break;
			D[j] += B;
			D[j+1]--;
		}
	}

	int l = 1, r = len;
	while (l + 1 < r){
		int m = (l + r) / 2;
		if (chk(m)) l = m;
		else r = m;
	}
	chk(l);

	int p = 0;
	for (int i=len-1;i>=0;i--){
		p = (p * B + F[i]) % l;
	}

	F[0] -= p;
	for (int i=0;;i++){
		if (F[i] >= 0) break;
		while (F[i] < 0){
			F[i] += B;
			F[i+1]--;
		}
	}

	F[l]++;
	printf ("%d\n",F[l-p]);

	return 0;
}