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;
#define ll long long
#define pb push_back
#define f first
#define s second
#define pii pair<int,int>
#define forn(a,b,c) for(int a=b;a<=c;a++)
#define ford(a,b,c) for(int a=b;a>=c;a--)
const int N=2e5+5;
int n,t;
char a[N];
pair<char,char>q[N];
int main()
{
    scanf("%d%d",&n,&t);
    forn(i,1,n){
        scanf(" %c",&a[i]);
    }
    forn(i,1,t){
        scanf(" %c %c",&q[i].f,&q[i].s);
    }
    int l=1,r=n;
    ford(i,t,1){
        if(q[i].f==a[l]&&q[i].s=='L'){
            l++;
        }
        else if(q[i].f==a[l-1]&&q[i].s=='R'){
            l--;
        }
        if(q[i].f==a[r]&&q[i].s=='R'){
            r--;
        }
        else if(q[i].f==a[r+1]&&q[i].s=='L'){
            r++;
        }
    }
    printf("%d\n",max(0,r-l+1));
    return 0;
}
