#include<map>

#include<queue>

#include<cstdio>

#include<cstdlib>

#include<cstring>

#include<iostream>

#include<algorithm>

#define maxn 100010

#define debug(a) cout << #a << " " << a << endl

using namespace std;

typedef long long ll;

ll a[maxn];

map<ll,int> mm;

int main() {

    a[] = ,a[] = ;

    mm[] = ,mm[] = ;

    for( int i=; i<=maxn; i++ ) {//打表

        a[i] = a[i-] + a[i-];

        mm[a[i]] = i;  //用map使值和对应的位置形成键值对方便查找

    }

    string s;

    while( cin >> s ) {

        ll sum = ;

        for( int i=; i<s.length(); i++ ) {

            sum =  sum *  + s[i] - '';

        }

        cout << mm[sum] << endl;

    }

    return ;

}