You are given a positive integer n, written without leading zeroes (for example, the number 04 is incorrect). 

In one operation you can delete any digit of the given integer so that the result remains a positive integer without leading zeros.

Determine the minimum number of operations that you need to consistently apply to the given integer n to make from it the square of some positive integer or report that it is impossible.

An integer x is the square of some positive integer if and only if x=y^2 for some positive integer y.

Input

The first line contains a single integer n (1 ≤ n ≤ 2 ⋅ 10^{9}). The number is given without leading zeroes.

Output

If it is impossible to make the square of some positive integer from n, print -1. In the other case, print the minimal number of operations required to do it.

Examples

Input

8314


Output

2


Input

625


Output

0


Input

333


Output

-1

Note

In the first example we should delete from 8314 the digits 3 and 4. After that 8314 become equals to 81, which is the square of the integer 9.

In the second example the given 625 is the square of the integer 25, so you should not delete anything. 

In the third example it is impossible to make the square from 333, so the answer is -1.
//Some of the methods are copied from GeeksforGeeks Website  
import java.util.*;
import java.lang.*;
import java.io.*;
public class Main
{ 
  static  Reader sc=new Reader();
  // static FastReader sc=new FastReader(System.in);
  static boolean valid(String x,String y)
   {
      int ly=y.length();
      int lx=x.length();
      int ind=0;
      for(int i=0;i<ly;i++)
        {
           if(y.charAt(i)==x.charAt(ind))
            {
               ind++;
            }
          if(ind==lx) return true;
        }
   return false;
   }
 public static void main (String[] args) throws java.lang.Exception
   {
	try{
	    /*
	        int n=sc.nextInt();
	        ArrayList<Integer> al=new ArrayList<>();
	        ArrayList<Long> al=new ArrayList<>();
	        Set<Integer> set=new HashSet<>();
	        Collections.sort(al,Collections.reverseOrder());
	     
	        long n=sc.nextLong();
	        for(int i=0;i<n;i++) 
	        String s=sc.next();
	        StringBuilder sb=new StringBuilder();
	     */
		  int t = 1;//sc.nextInt();
		  while(t-->0)
		    { 
		       long n=sc.nextLong();
		       long min=long_max;
		       for(long i=1; ; i++)
		         {
		            long num=i*i;
		            if(num>n)
		             break;
		          String x=Long.toString(num);
		          String y=Long.toString(n);
		           if(valid(x,y))
		            {
		               long ans=y.length()-x.length();
		               min=Math.min(min,ans);
		            }
		         }
		      out.println(min==long_max?"-1":min);
		    }
	     out.flush();
	     out.close();
	   }     
	catch(Exception e)
		 {}
	}
 
 /*
   ...SOLUTION ENDS HERE...........SOLUTION ENDS HERE...
 */
 
static void flag(boolean flag)
   {
       out.println(flag ? "YES" : "NO");
       out.flush();
   }
   
 /*                     
    Map<Long,Long> map=new HashMap<>();
             for(int i=0;i<n;i++)
               {
                  if(!map.containsKey(a[i]))
                   map.put(a[i],1);
                 else
                   map.replace(a[i],map.get(a[i])+1);
               }
     
    Set<Map.Entry<Long,Long>> hmap=map.entrySet();
             for(Map.Entry<Long,Long> data : hmap)
               {
          
               }
       
   Iterator<Integer> it = set.iterator();
          while(it.hasNext()) 
           { 
            int x=it.next();
           }
   */

static void print(int a[])
  {
     int n=a.length;
     for(int i=0;i<n;i++)
       {
          out.print(a[i]+" ");
       }
     out.println();
     out.flush();
  }
static void print(long a[])
  {
     int n=a.length;
     for(int i=0;i<n;i++)
       {
          out.print(a[i]+" ");
       }
     out.println();
     out.flush();
  } 
static void print_int(ArrayList<Integer> al)
  {
     int si=al.size();
     for(int i=0;i<si;i++)
       {
          out.print(al.get(i)+" ");
       }
     out.println();
     out.flush();
  }
static void print_long(ArrayList<Long> al)
  {
     int si=al.size();
     for(int i=0;i<si;i++)
       {
          out.print(al.get(i)+" ");
       }
     out.println();
     out.flush();
  }

static class Graph
  {
        int v;
        ArrayList<Integer> list[];
        Graph(int v)
        {
            this.v=v;
            list=new ArrayList[v+1];
            for(int i=1;i<=v;i++)
                list[i]=new ArrayList<Integer>();
        }
        void addEdge(int a, int b)
        {
            this.list[a].add(b);
        }
    }
static void DFS(Graph g, boolean[] visited, int u)
	{
        visited[u]=true;
        int v=0;
        for(int i=0;i<g.list[u].size();i++)
        {
            v=g.list[u].get(i);
            if(!visited[v])
               DFS(g,visited,v);
        }
  } 
  
// static class Pair
//    {
//       int x,y;
//       Pair(int x,int y)
//        {
//           this.x=x;
//           this.y=y;
//        }
//    }
   
static long sum_array(int a[])
 {
    int n=a.length;
    long sum=0;
    for(int i=0;i<n;i++)
     sum+=a[i];
    return sum;
 }
static long sum_array(long a[])
 {
    int n=a.length;
    long sum=0;
    for(int i=0;i<n;i++)
     sum+=a[i];
    return sum;
 }

 static void sort(int[] a) 
   {
		ArrayList<Integer> l=new ArrayList<>();
		for (int i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
static void sort(long[] a) 
   {
		ArrayList<Long> l=new ArrayList<>();
		for (long i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}

static void reverse_array(int a[])
 {
    int n=a.length;
    int i,t; 
    for (i = 0; i < n / 2; i++) { 
            t = a[i]; 
            a[i] = a[n - i - 1]; 
            a[n - i - 1] = t; 
        } 
 }
static void reverse_array(long a[])
 {
    int n=a.length;
    int i; long t; 
    for (i = 0; i < n / 2; i++) { 
            t = a[i]; 
            a[i] = a[n - i - 1]; 
            a[n - i - 1] = t; 
        } 
 }
 
static long gcd(long a, long b) 
    { 
        if (a == 0) 
            return b; 
          
        return gcd(b%a, a); 
    } 
static int gcd(int a, int b) 
    { 
        if (a == 0) 
            return b; 
          
        return gcd(b%a, a); 
    } 

   static class FastReader{
 
        byte[] buf = new byte[2048];
        int index, total;
        InputStream in;
 
        FastReader(InputStream is) {
            in = is;
        }
 
        int scan() throws IOException {
            if (index >= total) {
                index = 0;
                total = in.read(buf);
                if (total <= 0) {
                    return -1;
                }
            }
            return buf[index++];
        }
 
        String next() throws IOException {
            int c;
            for (c = scan(); c <= 32; c = scan());
            StringBuilder sb = new StringBuilder();
            for (; c > 32; c = scan()) {
                sb.append((char) c);
            }
            return sb.toString();
        }
 
        int nextInt() throws IOException {
            int c, val = 0;
            for (c = scan(); c <= 32; c = scan());
            boolean neg = c == '-';
            if (c == '-' || c == '+') {
                c = scan();
            }
            for (; c >= '0' && c <= '9'; c = scan()) {
                val = (val << 3) + (val << 1) + (c & 15);
            }
            return neg ? -val : val;
        }
 
        long nextLong() throws IOException {
            int c;
            long val = 0;
            for (c = scan(); c <= 32; c = scan());
            boolean neg = c == '-';
            if (c == '-' || c == '+') {
                c = scan();
            }
            for (; c >= '0' && c <= '9'; c = scan()) {
                val = (val << 3) + (val << 1) + (c & 15);
            }
            return neg ? -val : val;
        }
    }
   
    static class Reader 
    { 
        final private int BUFFER_SIZE = 1 << 16; 
        private DataInputStream din; 
        private byte[] buffer; 
        private int bufferPointer, bytesRead; 
  
        public Reader() 
        { 
            din = new DataInputStream(System.in); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public Reader(String file_name) throws IOException 
        { 
            din = new DataInputStream(new FileInputStream(file_name)); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public String readLine() throws IOException 
        { 
            byte[] buf = new byte[64]; // line length 
            int cnt = 0, c; 
            while ((c = read()) != -1) 
            { 
                if (c == '\n') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        } 
  
        public int nextInt() throws IOException 
        { 
            int ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do
            { 
                ret = ret * 10 + c - '0'; 
            }  while ((c = read()) >= '0' && c <= '9'); 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public long nextLong() throws IOException 
        { 
            long ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public double nextDouble() throws IOException 
        { 
            double ret = 0, div = 1; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
  
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
  
            if (c == '.') 
            { 
                while ((c = read()) >= '0' && c <= '9') 
                { 
                    ret += (c - '0') / (div *= 10); 
                } 
            } 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        private void fillBuffer() throws IOException 
        { 
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
            if (bytesRead == -1) 
                buffer[0] = -1; 
        } 
  
        private byte read() throws IOException 
        { 
            if (bufferPointer == bytesRead) 
                fillBuffer(); 
            return buffer[bufferPointer++]; 
        } 
  
        public void close() throws IOException 
        { 
            if (din == null) 
                return; 
            din.close(); 
        } 
    }
  static  PrintWriter out=new PrintWriter(System.out);
  static int int_max=Integer.MAX_VALUE;
  static int int_min=Integer.MIN_VALUE;
  static long long_max=Long.MAX_VALUE;
  static long long_min=Long.MIN_VALUE;
}
// Thank You !