// CuttingBitString.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <cmath>
using namespace std;

char x[51];
long long put[24], sum;
int i, j, k, sumeTot;
int main()
{
	cin.getline(x, 51);
	int p=strlen(x);
	int puteri=1;
	put[1]=1;
	while(put[puteri]!=11920928955078125LL)
	{
		puteri++;
		put[puteri]=put[puteri-1]*5;
	}
	for(i=0; i<p; i++)
	{
		for(j=0; j<p; j++)
		{
			sum=0;
			for(k=j; k>=i; k--)
			{
				sum+=pow((double)2, (double)k-i)*(x[k]-48);
				//cout<<sum<<"\n";
			}
			for(k=1; k<=puteri; k++)
			{
				if(sum==put[k] && sum!=0)
				{
					a[i][j]=1;
				}
				if(sum>put[k])
					break;
			}
		}
	}
	if(sumeTot)
		cout<<sumeTot;
	else
		cout<<-1;
}