void main()
{
	char c[100],d[100],e='a';
    long int a,b,m,k,s=0,p,q,i=0,j;
	scanf("%d%s%d",&a,c,&b);
    m=strlen(c);
	while(c[i]!=0)
	{
		if('A'<=c[i]&&c[i]<='Z')
			c[i]+='a'-'A';
		i++;
	}
	for(i=0;i<m;i++)
	{
		if(a<=10)
		k=c[i]-48;
		else 
		{
			if(48<=c[i]&&c[i]<=57)
				k=c[i]-48;
			else
			{
				k=9;
				while(e<=c[i])
				{
					k=k++;
					e++;
				}
			}
		}

		for(j=1;j<(m-i);j++)
		    k=k*a;
		s=s+k;
		e='a';
	}
	i=0;
	e='A';
	if(s==0)
	printf("0");
	else
	{
		while(s>0)
	{
		p=s/b;
		q=s%b;
		s=p;
		if(0<=q&&q<=9)
			d[i]=q+48;
		else
			for(j=10;j<=q;j++)
			{
				d[i]=e;
				e++;
			}
        i++;
		e='A';
	}
	i--;
	for(;i>=0;i--)
	printf("%c",d[i]);
	}
}