#include<bits/stdc++.h>
using namespace std;
int main()
{
    string n;
    cin>>n;
    int s = 0;
    long long k = 1;
    for(int i = n.size()-1;i>=0;i--)
    {
        if(n[i] <= '9' && n[i] >='0')
        {
            s+=(n[i]-48) * k;
        }
        else if(n[i] <= 'Z' && n[i]>= 'A')
        {
            s+=(n[i]-55) * k;
        }
        k=k*16;
    }
    cout<<s;
}
/**************************************************************
	Problem: 1292
	User: wuyichen
	Language: C++
	Result: Wrong Answer
****************************************************************/