#include<bits/stdc++.h>
using namespace std;
int f[12],lg[600];
void get(){
    for(int i=2;i<=10;i++) f[i]=2*f[i-1]+i+1;
}
int main()
{
    freopen("movement.in","r",stdin);
    freopen("movement.out","w",stdout);
    get();
    string s;
    cin>>s;
    int n=s.size(),flag=0;
    for(int i=0;i<n-1;i++){
        if(s[i]!='1') flag++;
    }
    if(flag){
        int ans=0;
        while(n){
            ans++;
            n>>=1;
        }
        cout<<f[ans]<<endl;
    }
    else cout<<1<<endl;
    return 0;
}