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
#include <stdio.h>
#include <string.h>
#include <algorithm>

using namespace std;

#define N 220000

struct Node {
    char a, b;
};

int n, m;
char s[N];
Node a[N];

int main() {
    scanf("%d%d", &n, &m); getchar();
    scanf("%s", s + 1); getchar();
    for (int i = 0; i < m; ++i) {
        scanf("%c %c", &a[i].a, &a[i].b); getchar();
    }
    int l = 1, r = n;
    for (int i = m - 1; i >= 0; --i) {
        if (a[i].b == 'L') {
            if (a[i].a == s[l]) ++l;
            if (r < n && a[i].a == s[r + 1]) ++r;
        } else if (a[i].b == 'R') {
            if (a[i].a == s[r]) --r;
            if (l > 1 && a[i].a == s[l - 1]) --l;
        }
    }
    printf("%d\n", max(r - l + 1, 0));
    return 0;
}
