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 <cmath>
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <iomanip>
#include <map>
#include <stack>
#include <queue>

using namespace std;

typedef long long ll;



int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int n,q;
    char s[200010],t[200010],d[200010];
    cin>>n>>q;
    s[0]='_';
    for(int i=1;i<=n;i++) cin>>s[i];
    s[n+1]='_';
    for(int i=0;i<q;i++) cin>>t[i]>>d[i];
    
    int l=0,r=n+1;
    for(int i=q-1;i>=0;i--){
        if(t[i]==s[l]&&d[i]=='R') l--;
        else if(t[i]==s[l+1]&&d[i]=='L') l++;
        if(t[i]==s[r]&&d[i]=='L') r++;
        else if(t[i]==s[r-1]&&d[i]=='R') r--;
    }
    
    cout<<r-l-1<<endl;
}