#include<iostream>
using namespace std;

int main()
{
    char hexa;
    int num = 0;
    while ( (hexa = cin.get()) != '\n')
      if (hexa >= '0' && hexa <= '9')
         num = 16*num + hexa -'0';
      else
         num = 16*num + hexa -'A' + 10;
         
    cout << num <<endl;

    system("pause");
    return 0;
}