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>
#define N 500005

using namespace std;

int n,m;char s[N],ss[N][2],op[N][2];

inline bool check(int x,int y){
    for (int i=1;i<=m;i++){
        if (s[x]==ss[i][1]){
            if (op[i][1]=='L') x--;
            else x++;
        }
    }
    return x==y;
}

int main(){
    scanf("%d%d",&n,&m);
    scanf("%s",s+1);
    for (int i=1;i<=m;i++){
        scanf("%s",ss[i]+1);
        scanf("%s",op[i]+1);
    }int ans=n;
    int l=1;int r=n;
    int L=1;int R=n;
    while (l+1<r){
        int mid=(l+r)>>1;
        if (check(mid,0)) l=mid;
        else r=mid;
    }
    if (check(r,0)) ans-=r;
    else if (check(l,0)) ans-=l;
    while (L+1<R){
        int mid=(L+R)>>1;
        if (check(mid,n+1)) R=mid;
        else L=mid;
    }
    if (check(L,n+1)) ans-=n-L+1;
    else if (check(R,n+1)) ans-=n-R+1;
    printf("%d\n",ans);
    return 0;
}