65535

#include<stdio.h>
#include<string.h>
#include<math.h>
int main()
{char a[20];int b[20];int len,i,k=0;long long sum=0,sum1;//double sum=0,sum1;gets(a);len=strlen(a);for(i=len-1;i>=0;i--){sum1=0;if(a[i]>='A'&&a[i]<='F'){b[i]=(int)(a[i]-'A'+10);sum1=b[i]*pow(16,k++);}else if(a[i]>='0'&&a[i]<='9'){ 	b[i]=(int)(a[i]-'0');sum1=b[i]*pow(16,k++);}sum+=sum1;}printf("%lld\n",sum);//printf("%.0lf",sum);return 0;  	
}