# include<iostream>
# include<stdio.h>
# include<string.h>
# define MAXN 100+10
char s[MAXN][MAXN];
char ss[MAXN][MAXN];
int pow(int base,int n)
{
int i,s=1;
for(i=1;i<=n;i++)
s=s*base;
return s;
}
using namespace std;
int main()
{
int a[100];
int base,n;
scanf("%d %d",&base,&n);
int i,t;
int s;
int m=0;
while(n)
{
t=n%base;
a[m++]=t;
n=n/10;
}
s=0;
for(i=0;i<m;i++)
s=s+a[i]*pow(base,i);
printf("%d",s);
return 0;
}