"简简单单"

求求了点个赞吧!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

#include<bits/stdc++.h>
using namespace std;
long long d=1,ans;
char s[1005];
int main(){
    cin>>s;
    int a=s[0]=='-'?1:0;
    for(int i=strlen(s)-1;i>=a;i--){
        ans+=(s[i]-'0')*d;
        d*=4;
    }
    if(a==1) cout<<'-';
    cout<<ans;
    return 0;
}