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<cstdio>
#include<iostream>
int n,q;
const int N=2e5+5;
char s[N],t[N],d[N];
bool check(int x,int p=0) {
    for(int i=1;i<=q&&x>0&&x<=n;i++) {
        if(t[i]==s[x]) d[i]=='L'?x--:x++;
    }
    return x==p;
}
int main() {
    scanf("%d%d",&n,&q);
    scanf("%s",s+1);
    for(int i=1;i<=q;i++) {
        getchar();
        scanf("%c %c",t+i,d+i);
    }
    int low,upp,l=0,r=n+1,mid;
    while(r-l>1) {
        mid=(l+r)>>1;
        if(check(mid)) l=mid;
        else r=mid;
    }
    low=l;l=1,r=n+1;
    while(l<r) {
        mid=(l+r)>>1;
        if(check(mid,n+1)) r=mid;
        else l=mid+1;
    }upp=r;
    printf("%d\n",upp-low-1);
    return 0;
}
