#include <iostream>
#include <cstdio>
using namespace std;

char c[16],ch;
int i,j,hex_len=0;
unsigned long long dec_hex=0;


int main()
{
  while((ch=getchar()) != '\n')
  {
    hex_len++;
    c[hex_len]=getchar();
  }

  for(i=1;i<=hex_len;i++)
  {
    switch(c[i])
    {
      case 'A': j=10; break;
      case 'B': j=11; break;
      case 'C': j=12; break;
      case 'D': j=13; break;
      case 'E': j=14; break;
      case 'F': j=15; break;
      default: j=c[i]-48; break;
    }
    dec_hex=dec_hex*16+j;
  }

  cout << dec_hex;
  return 0;
}