// 基础练习 十六进制转十进制
#include <stdio.h>
#include <string.h>
#include <math.h>

int main()
{
	char strHex[8];
	int i = 0, len = 0, temp = 0;
	__int64 nDec = 0;
	
	gets(strHex);
	
	len = strlen(strHex);
	for (i = 0; strHex[i] != '\0'; ++i)
	{
		switch(strHex[i])
		{
		case 'A': temp = 10; break;
		case 'B': temp = 11; break;
		case 'C': temp = 12; break;
		case 'D': temp = 13; break;
		case 'E': temp = 14; break;
		case 'F': temp = 15; break;
		default: temp = strHex[i]-'0'; break;
		}
		nDec += (temp*pow(16,len-1-i));
	}
	printf("%I64d",nDec);
	
	return 0;
}