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<bits/stdc++.h>
#define rep(i, n) for(int i = 1; i <= n; ++i)
using namespace std;
typedef long long ll;

const int maxn = 202000;
int n, q, lb, rb;
char s[maxn], t[maxn], d[maxn];

int main() {
    scanf("%d %d\n%s\n", &n, &q, s + 1);
    lb = 0, rb = n + 1; // (lb, rb) available
    rep(i, q) scanf("%c %c\n", &t[i], &d[i]);

    for(int i = q; i ; --i) {
        if(s[lb+1]==t[i] && d[i]=='L') lb++;
        if(s[rb-1]==t[i] && d[i]=='R') rb--;

        if(s[lb]==t[i] && d[i]=='R') lb--;
        if(s[rb]==t[i] && d[i]=='L') rb++;
    }

    printf("%d\n", rb - lb - 1);

    return 0;
}