//*???2010?10?26?*
//*??????*
//******************************************
int main()//???
{//?????
	int a=0,b=0,shijinzhi=0,weishu=0,i=0,j=0,shuchu[1000];//???????a?????????b?????????shijinzhi?????????????????weishu????????shuchu?????
	char shuru[1000]="abcdefg";//????????????
	cin>>a;
	cin>>shuru;
	cin>>b;//???????????????????????
	weishu=strlen(shuru);//????????
	for(i=0;i<=weishu-1;i++)
	{
		if(('A'<=shuru[i])&&(shuru[i]<='Z'))
			shuru[i]=shuru[i]-'A'+10;
		else if(('a'<=shuru[i])&&(shuru[i]<='z'))
			shuru[i]=shuru[i]-'a'+10;
		else if(('0'<=shuru[i])&&(shuru[i]<='9'))
			shuru[i]=shuru[i]-'0';
	}//?????
	for(i=0;i<=weishu-1;i++)
	{
		 shijinzhi=shijinzhi+(int)(shuru[i]*pow(1.0*a,1.0*(weishu-i-1)));
	}//????????
	if(shijinzhi==0)
		printf("%d",shijinzhi);//???????????0??????
	if(shijinzhi!=0)
	{
		 for(i=0;shijinzhi!=0;i++)
		 {
			shuchu[i]=shijinzhi%b;
			shijinzhi=shijinzhi/b;
		 }
		 for(j=i-1;j>=0;j--)
		 {
			  if((0<=shuchu[j])&&(shuchu[j]<=9))
				 printf("%d",shuchu[j]);
			  else if(shuchu[j]>=10)
			  {
				 shuchu[j]=shuchu[j]+'A'-10;
				 printf("%c",shuchu[j]);
		      }
		 }
	}//???0???????????????????
	printf("\n");//??
	return 0;
}//?????