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>
using namespace std;
int n, q;
string s;
char t[200000], d[200000];

int f(int x){
    int p=x;
    for(int i=0;i<q;i++){
        if(p<0||p>=n)break;
        if(s[p]==t[i]){
            if(d[i]=='L')p--;
            else p++;
        }
    }
    if(p<0)return -1;
    if(p>=n)return 1;
    return 0;
}


int main(void){
    cin>>n>>q>>s;
    for(int i=0;i<q;i++){
        cin>>t[i]>>d[i];
    }
    int a=n, l=-1, r=n;
    while(l+1<r){
        int m=(l+r)/2;
        if(f(m)==-1){
            l=m;
        }else{
            r=m;
        }
    }
    a-=l+1;
    l=-1, r=n;
    while(l+1<r){
        int m=(l+r)/2;
        if(f(m)==1){
            r=m;
        }else{
            l=m;
        }
    }
    a-=n-r;
    cout<<a<<endl;
}
