There are N squares numbered 1 to N from left to right. Each square has a character written on it, and Square i has a letter s_i. Besides, there is initially one golem on each square.

Snuke cast Q spells to move the golems.

The i-th spell consisted of two characters t_i and d_i, where d_i is `L` or `R`. When Snuke cast this spell, for each square with the character t_i, all golems on that square moved to the square adjacent to the left if d_i is `L`, and moved to the square adjacent to the right if d_i is `R`.

However, when a golem tried to move left from Square 1 or move right from Square N, it disappeared.

Find the number of golems remaining after Snuke cast the Q spells.

Constraints

* 1 \leq N,Q \leq 2 \times 10^{5}
* |s| = N
* s_i and t_i are uppercase English letters.
* d_i is `L` or `R`.

Input

Input is given from Standard Input in the following format:


N Q
s
t_1 d_1
\vdots
t_{Q} d_Q


Output

Print the answer.

Examples

Input

3 4
ABC
A L
B L
B R
A R


Output

2


Input

8 3
AABCBDBA
A L
B R
A R


Output

5


Input

10 15
SNCZWRCEWB
B R
R R
E R
W R
Z L
S R
Q L
W L
B R
C L
A L
N L
E R
Z L
S L


Output

3
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int Q = sc.nextInt();
        char[] s = sc.next().toCharArray();
        char[] t = new char[Q];
        char[] d = new char[Q];

        for(int i=0; i<Q; i++) {
            t[i] = sc.next().charAt(0);
            d[i] = sc.next().charAt(0);
        }

        // 落ちる区間を二分探索 左側
        int l = 0;
        int r = N/2;
        int center=0;
        while(l<=r) {
            center = (l+r)/2;
            if (!isExist(center,s,t,d)) {
                l = center + 1;
                center++;
            } else {
                r = center - 1;
            }
        }
        int left = center;

        // 落ちる区間を二分探索 右側
        l = N/2 + 1;
        r = N-1;
        center=0;
        while(l<=r) {
            center = (l+r)/2;
            if (isExist(center,s,t,d)) {
                l = center+1;
                center++;
            } else {
                r = center-1;
            }
        }
        int right = center;

        System.out.println(right - left);
   }

   // 最終的に生き残れるかどうか
   private static boolean isExist(int initialIndex, char[] s, char[] t, char[] d ) {
        int currentIndex = initialIndex;
        for (int i = 0; i < t.length ; i++) {
            if (s[currentIndex] == t[i]) {
                switch(d[i]) {
                    case 'L':
                        currentIndex--;
                        break;
                    case 'R':
                        currentIndex++;
                        break;
                }
                if(currentIndex<0 || currentIndex> s.length-1) return false;
            }
        }
        return true;
   }
}