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.
import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.util.*;
import java.util.Map.Entry;

public class Main
{
	private InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;
	private SpaceCharFilter filter;
	private PrintWriter pw;
	private long mod = 1000000000
			+ 7;

	private StringBuilder ans_sb;

	private void soln()
	{
		long x = nextLong();
		String s = new StringBuilder(
				Long.toString(
						x)).reverse()
								.toString();
		// debug(s);
		char[] arr = s
				.toCharArray();
		long tot = (int) Math
				.pow(2, s
						.length());
		int ans = Integer.MAX_VALUE;
		for (long i = 1; i < tot; i++)
		{
			long nn = 0;
			long pow1 = 1;
			int step = 0;
			boolean f = true;
			for (int j = 0; j < s
					.length(); j++)
			{
				long bit = ((i >> j)
						& 1);
				if (bit != 0)
				{
					step++;
					f = true;
					nn += ((long) (s
							.charAt(j)
							- '0'))
							* pow1;
					pow1 *= 10L;
					if (s.charAt(
							j) == '0')
						f = false;
				}
			}
			// debug(nn);
			long sqrt = (long) Math
					.sqrt(nn);
			if (sqrt * sqrt == nn
					&& f)
			{
				// debug(nn+" "+step);
				ans = Math
						.min(ans,
								s.length()
										- step);
			}
		}
		if (ans == Integer.MAX_VALUE)
			ans = -1;
		pw.println(
				ans);
	}

	class BitsetLong
	{

		static final int LOG = 6;
		static final int SIZE = 1 << LOG;
		static final int MASK = SIZE
				- 1;

		private long[] data;

		public BitsetLong(
				int n)
		{
			data = new long[(n >> LOG)
					+ 2];
		}

		void set(
				int i)
		{
			data[i >> LOG] |= 1L << (i
					& MASK);
		}

		void unset(
				int i)
		{
			data[i >> LOG] &= ~(1L << (i
					& MASK));
		}

		void flip(
				int i)
		{
			data[i >> LOG] ^= 1L << (i
					& MASK);
		}

		int get(int i)
		{
			return (int) ((data[i >> LOG] >>> (i
					& MASK))
					& 1);
		}

		void print()
		{
			for (int i = 0; i < data.length; i++)
			{
				System.out
						.print(Long
								.toString(
										data[i],
										2));
			}
			System.out
					.println();
		}

		long getWord(
				int i)
		{
			if (i <= -SIZE
					|| (i >> LOG)
							+ 1 >= data.length)
			{
				return 0;
			}
			int rem = i
					& MASK;
			int idx = i >> LOG;

			if (rem == 0)
			{
				return data[idx];
			}

			long head = idx < 0
					? 0
					: (data[idx] >>> rem);
			long tail = data[idx
					+ 1] << (SIZE
							- rem);

			return head
					| tail;
		}
	}

	int count(
			long[] bs,
			int len)
	{
		int ret = 0;
		for (int i = 0; i << 6 < len; i++)
		{
			if (((i + 1) << 6) <= len)
			{
				ret += Long
						.bitCount(
								bs[i]);
			} else
			{
				int rem = len
						& 63;
				ret += Long
						.bitCount(
								bs[i] << (64
										- rem));
			}
		}
		return ret;
	}

	private String solveEqn(
			long a,
			long b)
	{
		long x = 0,
				y = 1,
				lastx = 1,
				lasty = 0,
				temp;
		while (b != 0)
		{
			long q = a
					/ b;
			long r = a
					% b;
			a = b;
			b = r;
			temp = x;
			x = lastx
					- q * x;
			lastx = temp;
			temp = y;
			y = lasty
					- q * y;
			lasty = temp;
		}
		return lastx
				+ " "
				+ lasty;
	}

	private void debug(
			Object... o)
	{
		System.out
				.println(
						Arrays.deepToString(
								o));
	}

	private long pow(
			long a,
			long b,
			long c)
	{
		if (b == 0)
			return 1;
		long p = pow(
				a,
				b / 2,
				c);
		p = (p * p)
				% c;
		return (b
				% 2 == 0)
						? p
						: (a * p)
								% c;
	}

	private long gcd(
			long n,
			long l)
	{
		if (l == 0)
			return n;
		return gcd(
				l,
				n % l);
	}

	public static void main(
			String[] args)
			throws Exception
	{
		new Thread(
				null,
				new Runnable()
				{
					@Override
					public void run()
					{
						new Main()
								.solve();
					}
				},
				"1",
				1 << 26).start();
		// new Main().solve();
	}

	public StringBuilder solve()
	{
		InputReader(
				System.in);
		/*
		 * try { InputReader(new FileInputStream("C:\\Users\\hardik\\Desktop\\in.txt"));
		 * } catch(FileNotFoundException e) {}
		 */
		pw = new PrintWriter(
				System.out);
		// ans_sb = new StringBuilder();
		soln();

		pw.close();
		// System.out.println(ans_sb);
		return ans_sb;
	}

	public void InputReader(
			InputStream stream1)
	{
		stream = stream1;
	}

	private boolean isWhitespace(
			int c)
	{
		return c == ' '
				|| c == '\n'
				|| c == '\r'
				|| c == '\t'
				|| c == -1;
	}

	private boolean isEndOfLine(
			int c)
	{
		return c == '\n'
				|| c == '\r'
				|| c == -1;
	}

	private int read()
	{
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars)
		{
			curChar = 0;
			try
			{
				numChars = stream
						.read(buf);
			} catch (IOException e)
			{
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	private int nextInt()
	{
		int c = read();
		while (isSpaceChar(
				c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		int res = 0;
		do
		{
			if (c < '0'
					|| c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(
				c));
		return res
				* sgn;
	}

	private long nextLong()
	{
		int c = read();
		while (isSpaceChar(
				c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		long res = 0;
		do
		{
			if (c < '0'
					|| c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(
				c));
		return res
				* sgn;
	}

	private String nextToken()
	{
		int c = read();
		while (isSpaceChar(
				c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(
					c);
			c = read();
		} while (!isSpaceChar(
				c));
		return res
				.toString();
	}

	private String nextLine()
	{
		int c = read();
		while (isSpaceChar(
				c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(
					c);
			c = read();
		} while (!isEndOfLine(
				c));
		return res
				.toString();
	}

	private int[] nextIntArray(
			int n)
	{
		int[] arr = new int[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextInt();
		}
		return arr;
	}

	private long[] nextLongArray(
			int n)
	{
		long[] arr = new long[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextLong();
		}
		return arr;
	}

	private void pArray(
			int[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out
					.print(arr[i]
							+ " ");
		}
		System.out
				.println();
		return;
	}

	private void pArray(
			long[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out
					.print(arr[i]
							+ " ");
		}
		System.out
				.println();
		return;
	}

	private boolean isSpaceChar(
			int c)
	{
		if (filter != null)
			return filter
					.isSpaceChar(
							c);
		return isWhitespace(
				c);
	}

	private char nextChar()
	{
		int c = read();
		while (isSpaceChar(
				c))
			c = read();
		char c1 = (char) c;
		while (!isSpaceChar(
				c))
			c = read();
		return c1;
	}

	private interface SpaceCharFilter
	{
		public boolean isSpaceChar(
				int ch);
	}
}