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 <iostream>
#include <vector>
using namespace std;

int n,q;
string s;
vector<pair<char,char>> p(200100);

int del(int now){
    for(int i = 0;i < q;i++){
        if(s[now] == p[i].first){
            if(p[i].second == 'R') now++;
            else now--;
        }
        if(now < 0) return -1;
        if(now >= n) return 1;
    }
    return 0;
}

int main(void){
    cin >> n >> q >> s;
    for(int i = 0;i < q;i++){
        cin >> p[i].first >> p[i].second;
    }
    
    int left = -1,right = n+1,tmp;
    while(right-left > 1){
        int mid = (right+left)/2;
        if(del(mid) == -1) left = mid;
        else right = mid;
    }
    tmp = right;
    
    
    left = -1,right = n+1;
    int tmp2;
    while(right-left > 1){
        int mid = (right+left)/2;
        if(del(mid) == 1) right = mid;
        else left = mid;
    }
    tmp2 = right;
    
    cout << tmp2-tmp << endl;
    return 0;
}
