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>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
#define N 200010
ll n,q;
string s;
char t[N],d[N];
int solt(ll x){
    for(int i=0;i<q;i++){
	if(s[x]==t[i]){
	    if(d[i]=='L')x--;
	    if(d[i]=='R')x++;
	}
	if(x==-1)return 1;
	if(x==n)return 2;
    }
    return 0;
}
int main(){
    cin>>n>>q>>s;
    for(int i=0;i<q;i++){
	cin>>t[i]>>d[i];
    }
    //for(int i=0;i<n;i++)cout<<solt(i)<<" ";cout<<endl;
    ll mid;
    ll ls=-1,rs=n;
    while(ls<rs-1){
	mid=(ls+rs)/2;
	if(solt(mid)==1)ls=mid;
	else rs=mid;
    }
    ll lt=-1,rt=n;
    while(lt<rt-1){
	mid=(lt+rt)/2;
	if(solt(mid)==2)rt=mid;
	else lt=mid;
    }
    //cout<<rt<<" "<<ls<<endl;
    cout<<rt-ls-1<<endl;
    return 0;
}
