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>
using namespace std;
const int mx = 200005;
int n, q, l, r, a[2];
char s[mx], t1, t2;
pair<char, bool> p[mx];

bool C(int now, bool left){
    for(int i = 0; i < q; i++){
        if(p[i].first == s[now]){
            if(now == 0 && p[i].second) return !left;
            if(now == n-1 && !(p[i].second)) return left;
            now += p[i].second ? -1 : 1;
        }
    }
    return true;
}
int main(){
    scanf("%d%d%s\n", &n, &q, s);
    for(int i = 0; i < q; i++){
        scanf("%c %c\n", &t1, &t2);
        p[i] = make_pair(t1, t2 == 'L');
    }
    for(int i = 0; i < 2; i++){
        l = -1; r = n;
        while(l+1 < r){
            int mid = (l+r) / 2;
            (C(mid, i == 0)^(i == 0) ? l : r) = mid;
        }
        a[i] = r;
    }
    printf("%d\n", a[1] - a[0]);
}