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.

//package cf;
import java.io.*;
import java.util.*;
import java.util.jar.JarOutputStream;

public class T_class {
    static int p=1000000007;
    static int max=(int)1e5;
    static List<Integer> l1=new ArrayList<>();
    static boolean prime[]=new boolean[max];
    static long fact[]=new long[3_000_00];
    static class  pr_int
    {
        int first;
        int second;
        public pr_int(int first, int second) {
            this.first = first;
            this.second = second;
        }
    }
    static  long anss=0;
    public static void main(String[] args) throws Exception {
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(java.io.FileDescriptor.out), "ASCII"), 512);
        FastReader sc = new FastReader();
        int t =1;//sc.nextInt();//sc.nextInt();
        StringBuilder sb2 = new StringBuilder();
        int t2 = t;
        while (t-- > 0) {
            long n=sc.nextLong();
            int ans=Integer.MAX_VALUE;
            char ar[]=(n+"").toCharArray();
            for(long i=1;i<=Math.sqrt(n);i++)
            {
                char tar[]=((i*i)+"").toCharArray();
                int c=0;
                for(int j=0;j<ar.length;j++)
                {
                    if(ar[j]==tar[c])
                        c++;
                    if(c==tar.length)
                        break;
                }
                if(c==tar.length)
                ans=Math.min(ans,ar.length-tar.length);
            }
            System.out.println(ans==Integer.MAX_VALUE?-1:ans);
        }
        System.out.println(sb2.toString());
        out.flush();

    }

    private static void addto(PriorityQueue<pr_int> p1, PriorityQueue<pr_int> p2, pr_int cur1) {
        if(cur1.second==0)
            return;
        if(cur1.second>=2)
        p2.add(cur1);
    else
        p1.add(cur1);
    }

    public static  boolean isp(int n)
    {
        if(n==2||n==3||n==5||n==7||n==11||n==13||n==17)
        {
            return true;
        }
        return false;
    }
    private static String move(int[] i, String cur) {
        char ar[]=cur.toCharArray();
        //  System.out.println(cur);
        int sum=(ar[i[0]]-'0')+(ar[i[1]]-'0');
        if(isp(sum))
        {
            char t=ar[i[0]];
            ar[i[0]]=ar[i[1]];
            ar[i[1]]=t;
        }
        //System.out.println(String.valueOf(ar));
        return String.valueOf(ar);
    }

    static long lcm(long a,long b)
    {
        return  a*b/gcd(a,b);
    }
    static boolean done=false;
    static long ret;
    public  static long tolong(char ar[])
    {
        long ans=0;
        for(char i:ar)
            ans=ans*10+ (i-'0');

        return ans;
    }
    public  static  void recur(char ar[],int n,int cur,long lcm,boolean con)
    {
        if(cur==n)
        {
            System.out.println(tolong(ar)+" "+lcm);
            done=tolong(ar)%lcm==0;
            if(done)
                ret=tolong(ar);
            return;
        }
        int lst=ar[cur]-'0';
        for(int i=con?ar[cur]-'0':0;i<=9;i++)
        {
            char prev=ar[cur];
            ar[cur]=(char) (i+'0');
            recur(ar, n, cur + 1, i==0?lcm:lcm(i,lcm),lst==i);
            ar[cur]=prev;
            if(done)
                return ;
        }
    }
    static long ansa(long l,long r,long s,long ss,int n,int ar[])
    {

        while(l<=r)
        {
            long mid=(l+r)/2;
            long tot=0;
            for(int i=0;i<n;i++)
            {
                tot+=Math.abs(ar[i]-mid);
            }

            if(tot*2<=s)
            {
                // System.out.println(s+" - "+(mid*n)+" <= "+ss);
                return mid;
            }
            else if(tot*2>s)
            {
                r=mid-1;
            }
            else
            {
                l=mid+1;
            }
        }
        return 1;
    }
    static void ruffle_sort(long[] a) {
        //shandom_ruffle
        Random r=new Random();
        int n=a.length;
        for (int i=0; i<n; i++) {
            int oi=Math.abs(r.nextInt(i+1));
            long temp=a[i];
            a[i]=a[oi];
            a[oi]=temp;
        }

        //sort
        Arrays.sort(a);
    }
    static void ruffle_sort(int[] a) {
        //shandom_ruffle
        Random r=new Random();
        int n=a.length;
        for (int i=0; i<n; i++) {
            int oi=Math.abs(r.nextInt(i+1));
            int temp=a[i];
            a[i]=a[oi];
            a[oi]=temp;
        }

        //sort
        Arrays.sort(a);
    }
    static long mod=(long) 1e9+7;
    private static long nC2(long n) {
        return n*(n-1)/2;
    }
    static long mul(long a, long b) {
        return a*b%mod;
    }

    static long add(long a, long b) {
        return (a+b)%mod;
    }
    static void precomp() {
        fact[0]=1;
        for (int i=1; i<fact.length; i++) fact[i]=mul(fact[i-1], i);
    }
    static long modInv(long x) {
        return pow(x, mod-2,mod);
    }
    static long nCk(int n, int k) {
        return mul(fact[n], mul(modInv(fact[k]), modInv(fact[n-k])));
    }


    private static List<Long> getdivisors(long n) {
        List<Long> l1=new ArrayList<>();
        for(long i=1;i<=Math.sqrt(n);i++)
        {
            if(n%i==0){
                l1.add(i);
                if(n/i!=i)
                    l1.add(n/i);
            }
        }
        // System.out.println(l1);
        Collections.sort(l1);
        return l1;
    }

    private static int count(int k, int l, String cur) {
        char ar[]=cur.toCharArray();
        int c=0;
        for(int i=k;i<=l;i++)
        {
            if(i=='1')
                c++;
        }
        return c;
    }

    private static String revese(String substring) {
        StringBuilder sb=new StringBuilder();
        sb.append(substring);
        sb=sb.reverse();
        return sb.toString();
    }


    static  int ht[]=new int[max];
    static class BIT {
        long[] tree;
        public BIT(int size) {
            tree = new long[size + 1];
        }
        public long sum(int i) {
            long ans = 0;
            while (i > 0) {
                ans += tree[i];
                i -= i & -i;
            }
            return ans;
        }

        public long query(int i, int j) {
            return sum(j) - sum(i - 1);
        }

        public void add(int i, long val) {
            while (i < tree.length) {
                tree[i] += val;
                i += i & -i;
            }
        }

        public void set(int i, long val) {
            add(i, val - query(i, i));
        }
    }
    public static long pow(long a,long b,long m)
    {
        long r=1;
        while(b!=1)
        {
            if(b%2!=0)
                r=(r*a)%m;
            b=b>>1;
            a=(a*a)%m;
        }
        return (r*a)%m;
    }
    public static long gcd(long a,long b)
    {
        if(b>a)
        {
            a=a^b;
            b=a^b;
            a=a^b;
        }
        if(b==0)
            return a;
        return gcd(b,a%b);
    }
    public static void extgcd(long a,long b)
    {/*
            if(a==0)
            {
                x=0;
                y=1;
                d=b;
                // return ;
            }
            else
            {

                extgcd(b%a,a);

                long t=y;
                y=x;
                x=t-(b/a)*x;
            }*/
    }
    static  Set<Integer > used=new HashSet<>();
    public static void dfs(List<Integer>[] adj, int u, int p, boolean[] vis,long ind[],long n)
    {
        // anss-=((ind[u]-1)*(ind[u]-2))/2>0&&!used.contains(u)?((ind[u]-1)*(ind[u]-2))/2:0;

        if(((ind[u]-1)*(ind[u]-2))/2>0)
        {
            //   System.out.println(u+" -- "+((ind[u]-1)*(ind[u]))/2);
            //   used.add(u);
        }
        vis[u]=true;
        int c=0;
        for(int v:adj[u])
        {
            if(v!=p&&vis[v])
            {
                //   System.out.println(u+" c--c"+v+" "+((ind[v]-1)*(ind[v]))/2);
                if(((ind[v]-1)*(ind[v]-2))/2>0) {
                    anss -= ((ind[v] - 1) * (ind[v] - 2)) / 2 > 0 && !used.contains(v) ? ((ind[v] - 1) * (ind[v] - 2)) / 2 : 0;
                    used.add(v);
                }
                if(((ind[u]-1)*(ind[u]-2))/2>0) {
                    anss -= ((ind[u] - 1) * (ind[u] - 2)) / 2 > 0 && !used.contains(u) ? ((ind[u] - 1) * (ind[u] - 2)) / 2 : 0;
                    used.add(u);
                }
                continue;
            }
            if(!vis[v])
            {
                c++;
                dfs(adj,v,u, vis,ind,n+1);
            }
        }
        if(c==0)
        {
            anss+=(n)*(n+1l)/2;
        }
        vis[u]=false;
    }
    public static void seive()
    {
        for(int i=0;i<max;i++)
            prime[i] = true;

        for(int p = 2; p*p <=max; p++)
        {
            // If prime[p] is not changed, then it is a prime
            if(prime[p] == true)
            {
                // Update all multiples of p
                for(int i = p*p; i <=max; i += p)
                    prime[i] = false;
            }
        }

        // Print all prime numbers
        for(int i = 2; i <= max; i++)
        {
            if(prime[i] == true)
            {
                l1.add(i);
            }
        }
    }
    public static boolean union(int a, int b, int p[], int r[]){
        // add your code here
        int pa=find(a,p,r);
        int pb=find(b,p,r);
        if(pa==pb)
            return true;
        if(pa!=pb)
        {
            if(r[pa]<r[pb])
            {
                p[pa]=pb;
            }
            else if(r[pa]>r[pb])
            {
                p[pb]=pa;
            }
            else
            {
                p[pa]=pb;
                r[pb]++;
            }
        }
        return false;
    }
    public static int find(int x,int p[],int r[])
    {
        if(p[x]==x)
            return x;
        p[x]=find(p[x],p,r);
        return p[x];
    }
    public static int binary_Search_upper(int[] ar,int l, int x)
    {
        int res=-1;
        int r=ar.length-1;
        while(l<=r)
        {
            int mid=(l+r)>>1;
            if(ar[mid]<=x)
            {
                res=mid;
                l=mid+1;
            }
            else if(ar[mid]>x)
            {
                //res=mid;
                r=mid-1;
            }
        }
        return res;
    }
    public static int binary_Search_lower(int[] ar, int x)
    {
        int res=ar.length;
        int l=0;int r=ar.length-1;
        while(l<=r)
        {
            int mid=(l+r)>>1;
            if(ar[mid]>=x)
            {
                res=mid;
                r=mid-1;
            }
            else
            {
                l=mid+1;
            }
        }
        return res;
    }
    int bit[]=new int[(int)1e6];
    public void update(int n,int val,int i)
    {
        i++;
        while(i<n)
        {
            bit[i]+=val;
            i+=(i)&(-i);
        }

    }
    public long query(int n,int i)
    {
        i++;
        long sum=0;
        while(i>0)
        {
            sum+=bit[i];
            i-=(i)&(-i);
        }
        return sum;
    }


    ///////////////////////////////////////////////////////////////////////////////////
    //////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader {

        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }


}
