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.
/**
 * Created by Baelish on 4/10/2018.
 */

import java.io.*;
import java.lang.reflect.Array;
import java.util.*;

import static java.lang.Math.*;

public class C {
    public static void main(String[] args) throws Exception {
        FastReader in = new FastReader(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        ArrayList<Integer> squares = new ArrayList<>();
        for(int i = 1; (long)i*(long)i <= (long)2e9; i++){
            squares.add(i*i);
        }

        int n = in.nextInt();
        pw.println(solve(squares, n));

        pw.close();
    }

    public static boolean containsSubsequence( String sequence, String subsequence) {
        if (subsequence.isEmpty()) {
            return true;
        }
        int subsequenceIndex = 0;
        for (int i = 0; i < sequence.length(); ++i) {
            if (sequence.charAt(i) == subsequence.charAt(subsequenceIndex)) {
                ++subsequenceIndex;
                if (subsequenceIndex == subsequence.length()) {
                    return true;
                }
            }
        }
        return false;
    }

    static int solve(ArrayList<Integer> g, int n){
        String s = Integer.toString(n);
        int min = Integer.MAX_VALUE;
        for(int i : g){
            String t = Integer.toString(i);
            if(containsSubsequence(s, t)){
                min = Math.min(s.length() - t.length(), min);
            }
        }
        if(min == Integer.MAX_VALUE) return -1;
        return min;
    }

    static void debug(Object... obj) {
        System.err.println(Arrays.deepToString(obj));
    }

    static class FastReader {
        InputStream is;
        private byte[] inbuf = new byte[1024];
        private int lenbuf = 0, ptrbuf = 0;
        static final int ints[] = new int[128];

        public FastReader(InputStream is) {
            for (int i = '0'; i <= '9'; i++) ints[i] = i - '0';
            this.is = is;
        }

        public int readByte() {
            if (lenbuf == -1) throw new InputMismatchException();
            if (ptrbuf >= lenbuf) {
                ptrbuf = 0;
                try {
                    lenbuf = is.read(inbuf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (lenbuf <= 0) return -1;
            }
            return inbuf[ptrbuf++];
        }

        public boolean isSpaceChar(int c) {
            return !(c >= 33 && c <= 126);
        }

        public int skip() {
            int b;
            while ((b = readByte()) != -1 && isSpaceChar(b)) ;
            return b;
        }

        public String next() {
            int b = skip();
            StringBuilder sb = new StringBuilder();
            while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != ' ')
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public int nextInt() {
            int num = 0, b;
            boolean minus = false;
            while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
            if (b == '-') {
                minus = true;
                b = readByte();
            }

            while (true) {
                if (b >= '0' && b <= '9') {
                    num = (num << 3) + (num << 1) + ints[b];
                } else {
                    return minus ? -num : num;
                }
                b = readByte();
            }
        }

        public long nextLong() {
            long num = 0;
            int b;
            boolean minus = false;
            while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
            if (b == '-') {
                minus = true;
                b = readByte();
            }

            while (true) {
                if (b >= '0' && b <= '9') {
                    num = (num << 3) + (num << 1) + ints[b];
                } else {
                    return minus ? -num : num;
                }
                b = readByte();
            }
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }
       /* public char nextChar() {
            return (char)skip();
        }*/

        public char[] next(int n) {
            char[] buf = new char[n];
            int b = skip(), p = 0;
            while (p < n && !(isSpaceChar(b))) {
                buf[p++] = (char) b;
                b = readByte();
            }
            return n == p ? buf : Arrays.copyOf(buf, p);
        }

        /*private char buff[] = new char[1005];
        public char[] nextCharArray(){
            int b = skip(), p = 0;
            while(!(isSpaceChar(b))){
                buff[p++] = (char)b;
                b = readByte();
            }
            return Arrays.copyOf(buff, p);
        }*/
    }
}