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 INF 1000000007
#define LINF 1000000000000000007
 
typedef long long i64;
typedef pair<i64,i64> P;


int n, q;
string s;
char t[202020], d[202020];

int main(){
	cin >> n >> q;
	cin >> s;
	for(int i = 0; i < q; i++){
		cin >> t[i] >> d[i];
	}
	
	int l = 0, r = n-1;
	int ansl = 0, ansr = 0;
	while(l <= r){
		int c = (l+r)/2, cc = (l+r)/2;
		for(int i = 0; i < q; i++){
			if(t[i] == s[c]){
				if(d[i] == 'L') c--;
				else c++;
			}
			if(c < 0){
				l = cc+1;
				ansl = cc+1;
				break;
			}
		}
		if(l != cc+1) r = cc-1;
	}
	
	l = ansl; r = n-1;
	while(l <= r){
		int c = (l+r)/2, cc = (l+r)/2;
		for(int i = 0; i < q; i++){
			if(t[i] == s[c]){
				if(d[i] == 'L') c--;
				else c++;
			}
			if(c >= n){
				r = cc-1;
				ansr = n-cc;
				break;
			}
		}
		if(r != cc-1) l = cc+1;
	}
	
	cout << n-(ansl + ansr) << endl;
	
	return 0;
}