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,ans;
char t[200000],d[200000];
string s;

int solve(int x){
    for(int i = 0;i < q;i ++){
        if(s[x]==t[i]) x += d[i]=='R'?1:-1;
        if(x==-1) return 0;
        else if(x==n) return n-1;
    }
    return -1;
}
int binary_search_ans(int ok,int ng,int p){
    while(abs(ok-ng)>1){
        int mid = (ok+ng)/2;
        if(solve(mid)==p){
            ok = mid;
        }else{
            ng = mid;
        }
    }
    return ok;
}

int main(){
    cin >> n >> q >> s;
    for(int i = 0;i < q;i ++){
        cin >> t[i] >> d[i];
    }
    ans += binary_search_ans(-1,n,0)+1;
    ans += n-binary_search_ans(n,-1,n-1);
    cout << n-ans << endl;
    return 0;
}