Levko loves strings of length n, consisting of lowercase English letters, very much. He has one such string s. For each string t of length n, Levko defines its beauty relative to s as the number of pairs of indexes i, j (1 ≤ i ≤ j ≤ n), such that substring t[i..j] is lexicographically larger than substring s[i..j].

The boy wondered how many strings t are there, such that their beauty relative to s equals exactly k. Help him, find the remainder after division this number by 1000000007 (109 + 7).

A substring s[i..j] of string s = s1s2... sn is string sisi + 1... sj.

String x = x1x2... xp is lexicographically larger than string y = y1y2... yp, if there is such number r (r < p), that x1 = y1, x2 = y2, ... , xr = yr and xr + 1 > yr + 1. The string characters are compared by their ASCII codes.

Input

The first line contains two integers n and k (1 ≤ n ≤ 2000, 0 ≤ k ≤ 2000).

The second line contains a non-empty string s of length n. String s consists only of lowercase English letters. 

Output

Print a single number — the answer to the problem modulo 1000000007 (109 + 7).

Examples

Input

2 2
yz


Output

26


Input

2 3
yx


Output

2


Input

4 7
abcd


Output

21962
import java.io.IOException;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.PrintStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author karan173
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastReader in = new FastReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskC
{
    int n, k;
    long mod = (long) (1e9 + 7);
    long dp[][];
    char s[];
    public void solve(int testNumber, FastReader in, PrintWriter out)
    {
        n = in.ni ();
        k = in.ni ();
        s = in.ns ().toCharArray ();
        dp = new long[n + 1][k + 1];
        Arrays.fill (dp[n], 0);
        dp[n][0] = 1;
        int greater[] = new int[n];
        int lesser[] = new int[n];
        for (int i = 0; i < n; i++)
        {
            greater[i] = 'z' - s[i];
            lesser[i] = s[i] - 'a';
        }
        long sumLess[] = new long[k + 1];
        Arrays.fill (sumLess, 0);
        for (int i = n - 1; i >= 0; i--)
        {
            for (int beauty = 0; beauty <= k; beauty++)
            {
                dp[i][beauty] = 0;
            }
        }
        for (int i = n - 1; i >= 0; i--)
        {
            for (int j = i; j < n; j++)
            {
                int numEqual = j - i;
                int after = n - j;
                int increase = (numEqual + 1) * after;
                for (int beauty = increase; beauty <= k; beauty++)
                {
                    dp[i][beauty] += dp[j + 1][beauty - increase] * greater[j];
                }
            }
            for (int beauty = 0; beauty <= k; beauty++)
            {
                //case lower
                long val = lesser[i] * dp[i + 1][beauty];
                dp[i][beauty] += val;
                dp[i][beauty] %= mod;
                dp[i][beauty] += sumLess[beauty];
                dp[i][beauty] %= mod;
                sumLess[beauty] += val;
                sumLess[beauty] %= mod;
                //case all equal -- CHECK
                if(beauty == 0)
                {
                    dp[i][beauty]++;
                    dp[i][beauty] %= mod;
                }
            }
        }
        out.println (dp[0][k]);

    }


}

class FastReader
{

    public InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private SpaceCharFilter filter;

    public FastReader(InputStream stream)
    {
        this.stream = stream;
    }

    public FastReader()
    {

    }

    public 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++];
    }

    public int ni()
    {
        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;
    }

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

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

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

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