You are given a huge decimal number consisting of n digits. It is guaranteed that this number has no leading zeros. Each digit of this number is either 0 or 1.

You may perform several (possibly zero) operations with this number. During each operation you are allowed to change any digit of your number; you may change 0 to 1 or 1 to 0. It is possible that after some operation you can obtain a number with leading zeroes, but it does not matter for this problem.

You are also given two integers 0 ≤ y < x < n. Your task is to calculate the minimum number of operations you should perform to obtain the number that has remainder 10^y modulo 10^x. In other words, the obtained number should have remainder 10^y when divided by 10^x.

Input

The first line of the input contains three integers n, x, y (0 ≤ y < x < n ≤ 2 ⋅ 10^5) — the length of the number and the integers x and y, respectively.

The second line of the input contains one decimal number consisting of n digits, each digit of this number is either 0 or 1. It is guaranteed that the first digit of the number is 1.

Output

Print one integer — the minimum number of operations you should perform to obtain the number having remainder 10^y modulo 10^x. In other words, the obtained number should have remainder 10^y when divided by 10^x.

Examples

Input


11 5 2
11010100101


Output


1


Input


11 5 1
11010100101


Output


3

Note

In the first example the number will be 11010100100 after performing one operation. It has remainder 100 modulo 100000.

In the second example the number will be 11010100010 after performing three operations. It has remainder 10 modulo 100000.
import java.util.*;

import javax.lang.model.util.ElementScanner6;

import java.io.*;

public class Main{

    public static void main(String[] args) {

        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader inp = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(inp, out);
        out.close();
        
        }



    static class Solver {


        class Node implements Comparable<Node>{
            int i;
            long c;
        
            Node(int i,long c)
            {
                this.i=i;
                this.c=c;


            }

        public int compareTo(Node n)
            {
                if(this.c==n.c)
                {
                    return Integer.compare(this.i, n.i);
                }
                return Long.compare(this.c, n.c);
            }
        }

        public boolean done(int[] sp,int[] par)
        {
            int root;

            root=findSet(sp[0],par);
            
        for(int i=1;i<sp.length;i++)
        {
                if(root!=findSet(sp[i], par))
                    return false;
        }
        return true;
        }
    public int findSet(int i,int[] par)
    {
        int x =i;
            boolean flag =false;
            while(par[i]>=0)
            {
                flag = true;
                i=par[i];
            }
            if(flag)
                par[x]=i;
            return i;
    }

    public void unionSet(int i,int j,int[] par)
    {
            int x = findSet(i, par);
            int y = findSet(j, par);
            if(x<y)
            {
                par[y]=x;
            }
            else
            {
                par[x]=y;
            }
    }

    public  long pow(long a, long b, long MOD) {
            if (b == 0) {
                return 1;
            }
            if (b == 1) {
                return a;
            }
            long val = pow(a, b / 2, MOD);
            if (b % 2 == 0) {
                return val * val % MOD;
            } else {
                return val * (val * a % MOD) % MOD;

            }
        
        }


        public void minPrimeFactor(int n,int[] s)
        {
            boolean prime[] = new boolean[n+1];
            Arrays.fill(prime, true);
            s[1]=1;
            s[2]=2;
            for(int i=4;i<=n;i+=2)
            {
                prime[i]=false;
                s[i]=2;
            }

            for(int i=3;i<=n;i+=2)
            {
                if(prime[i])
                {
                    s[i]=i;
                    for(int j=2*i;j<=n;j+=i)
                    {
                        prime[j]=false;
                        s[j]=i;
                    }
                }
            }
            
        }

        
        // public void findAllPrime(int n,ArrayList<Node> al,int s[])
        // {
        //     int curr = s[n];
        //     int cnt = 1;
        //     while(n>1)
        //     {
        //         n/=s[n];
        //         if(curr==s[n])
        //         {
        //             cnt++;
        //             continue;

        //         }
        //         Node n1 = new Node(curr,cnt);
        //         al.add(n1);

        //         curr=s[n];
        //         cnt=1;
        //     }
        // }

        

        public int binarySearch(int n,int k)
        {
            int left=1;
            int right=100000000+5;
            int ans=0;
            while(left<=right)
            {
                int mid = (left+right)/2;
                if(n/mid>=k)
                {
                    left = mid+1;
                    ans=mid;
                }
                else
                {
                    right=mid-1;
                }
            }

            return ans;
        }
        public boolean checkPallindrom(String s)
        {
            char ch[] = s.toCharArray();

            for(int i=0;i<s.length()/2;i++)
            {
                if(ch[i]!=ch[s.length()-1-i])
                    return false;
            }
            return true;
        }


        public void dfs_util(ArrayList<Integer>[] al,boolean vis[],int x,int cnt[],int sts[],int fts[],long sv[])
        {
                
            vis[x] = true;
            long min=Long.MAX_VALUE;
                sts[cnt[0]]=x+1;
                for(int i=0;i<al[x].size();i++)
                {
                    
                    if(!vis[al[x].get(i)])
                    {
                        cnt[0]++;
                        dfs_util(al, vis, al[x].get(i),cnt,sts,fts,sv);
                        if(sv[al[x].get(i)]<min&&sv[al[x].get(i)]!=-1)
                        {
                            min=sv[al[x].get(i)];
                        }
                        
                        
                    }    
                    
                }

            
                if(sv[x]==-1)
                {
                    if(min==Long.MAX_VALUE)
                    {
                        min=-1;
                    }
                    sv[x]=min;
                }
            
            
            return ;
        }

        public void dfs(ArrayList[] al,int sts[],int fts[],long sv[])
        {
            
        boolean vis[] = new boolean[al.length];
        int cnt[]= new int[2*al.length+2];
        for(int i=0;i<al.length;i++)
        {
                if(!vis[i])
                {
                    
                    dfs_util(al,vis,i,cnt,sts,fts,sv);
                }
        }
        }

        public void remove(ArrayList<Integer>[] al,int x)
        {
            for(int i=0;i<al.length;i++)
            {
                for(int j=0;j<al[i].size();j++)
                {

                    if(al[i].get(j)==x)
                        al[i].remove(j);

                }
            }
        }

        public int gcd(int a, int b) 
        { 
            if (a == 0) 
                return b; 
            return gcd(b % a, a); 
        }


        public void printDivisors(int n,ArrayList<Integer> al) 
        { 
            // Note that this loop runs till square root 
            for (int i=1; i<=Math.sqrt(n); i++) 
            { 
                if (n%i==0) 
                { 
                    // If divisors are equal, print only one 
                    if (n/i == i) 
                    {
                        al.add(i);
                    }
                      
        
                    else // Otherwise print both 
                    {
                        al.add(i);
                        al.add(n/i);
                    }
                        
                } 
            } 
        } 

        public static long constructSegment(long seg[],long arr[], int low,int high,int pos)
        {
            if(low==high)
            {
                seg[pos] = arr[low]; 
                return seg[pos];
            }
            int mid = (low+high)/2;
            long t1=constructSegment(seg, arr,low , mid,(2*pos)+1);
            long t2=constructSegment(seg,arr,mid+1,high,(2*pos)+2);
            seg[pos] = t1+t2;
            return seg[pos];

        }
        public static long querySegment(long seg[],int low,int high,int qlow, int qhigh,int pos)
        {
            
             if(qlow<=low&&qhigh>=high)
             {
                return seg[pos];
             }
             else if(qlow>high||qhigh<low )
             {
                 return 0;
             }
             else{
                long ans=0;
                int mid=(low+high)/2;
                ans+=querySegment(seg,low , mid, qlow, qhigh,  (2*pos)+1);
                ans+=querySegment(seg, mid+1, high, qlow, qhigh, (2*pos)+2);
               return ans; 
             }

        }
        public static int lcs( char[] X, char[] Y, int m, int n ) 
        { 
            if (m == 0 || n == 0) 
            return 0; 
            if (X[m-1] == Y[n-1]) 
            return 1 + lcs(X, Y, m-1, n-1); 
            else
            return Integer.max(lcs(X, Y, m, n-1), lcs(X, Y, m-1, n)); 
        } 

        public static long recursion(long start,long end,long cnt[],int a, int b)
        {

            long min=0;
            long count=0;
            int ans1=-1;
            int ans2=-1;
            int l=0;
            int r=cnt.length-1;
            while(l<=r)
            {
                int mid=(l+r)/2;
                if(cnt[mid]>=start)
                {
                    ans1=mid;
                    r=mid-1;
                }
                else
                {
                    l=mid+1;
                }
            }

            l=0;
            r=cnt.length-1;
            while(l<=r)
            {
                int mid=(l+r)/2;
                if(cnt[mid]<=end)
                {
                    ans2=mid;
                    l=mid+1;
                }
                else
                {
                    r=mid-1;
                }
            }
            
            if(ans1==-1||ans2==-1||ans2<ans1)
            {
                // System.out.println("min1 "+min);
                min=a;
                return a;

            }
            else
            {
                min=b*(end-start+1)*(ans2-ans1+1);
            }
            if(start==end)
            {
                // System.out.println("min "+min);
                return min;
            }
            long mid = (end+start)/2;
            min = Long.min(min,recursion(start, mid, cnt, a, b)+recursion(mid+1, end, cnt, a, b));
            // System.out.println("min "+min);
            return min;
        }

        public void dfs(int x, ArrayList<Integer> al[], boolean[] vis)
        {
            vis[x]=true;
            System.out.print((x+1)+" ");
            for(int i=0;i<al[x].size();i++)
            {
                if(!vis[al[x].get(i)])
                {
                    dfs(al[x].get(i),al,vis);
                }
            }
        }



      

        private void solve(InputReader inp, PrintWriter out1) {
                int  n = inp.nextInt();
                int x = inp.nextInt();
                int y = inp.nextInt();
                String s = inp.next();
                char ch[] = s.toCharArray();
                int ans=0;
                for(int i=n-1;i>=n-x;i--)
                {
                    if(n-1-i==y)
                    {
                        if(ch[i]!='1')
                        {
                            ans++;
                        }
                    }
                    else if (ch[i]!='0')
                    {
                        ans++;
                    }
                }
                System.out.println(ans);
        }
}





    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}
class ele{
    long value;
    long i;
    boolean flag;
    public ele(long value,long i)
    {
        this.value = value;
        this.i=i;
        this.flag = false;
    }
}