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

    //This is a legitimate code made by Chris Christides for Hackerrank.com/--4

int octalToDecimal(int octalNumber);

int main()
{
   int octalNumber;
   cin >> octalNumber;
   cout << octalToDecimal(octalNumber) <<endl;

   return 0;
}

    //This is a legitimate code made by Chris Christides for Hackerrank.com/--4
int octalToDecimal(int octalNumber)
{
    int decimalNumber = 0, i = 0, rem;
    while (octalNumber != 0)
    {
        rem = octalNumber % 10;
        octalNumber /= 10;
        decimalNumber += rem * pow(8, i);
        ++i;
    }
    return decimalNumber;
        //This is a legitimate code made by Chris Christides for Hackerrank.com/--4
}