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;
typedef long long ll;

int N, Q;
char s[202020];
char t[202020];
char d[202020];
int f[202020];
int check(int p){
    for(int i = 0; i < Q; i++){
        if(s[p] == t[i]){
            if(d[i]=='L')p--;
            else p++;
        }
        if(p < 1)return 1;
        if(p > N)return 3;
    }
    return 2;
}

int main(){

    cin >> N >> Q;
    for(int i = 1; i <= N; i++)cin >> s[i];
    for(int i = 0; i < Q; i++)cin >> t[i] >> d[i];
    f[0] = 1;
    f[N+1] = 3;
    int notR = 0, R = N + 1;
    while(notR + 1 < R){
        int p = (notR + R) / 2;
        if(check(p) == 3)R = p;
        else notR = p;
    }
    int L = 0, notL = N + 1;
    while(L + 1 < notL){
        int p = (L + notL) / 2;
        if(check(p) == 1)L = p;
        else notL = p;
    }
    cout << max(0, notR - notL + 1) << endl;

    return 0;
}
