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 F first
#define S second
#define PB push_back
#define all(x) x.begin(), x.end()

typedef long long ll; 
typedef long double ld;

const int N = 1000 * 100 + 10, M = 210; 
const int mod = 1000 * 1000 * 1000 + 7;

string s;
string t, x;
int n, q;

int get(int i)
{
	for(int j = 0; j < q; j++)
	{
		if(s[i] != t[j]) continue;
		if(x[j] == 'L') i--;
		else i++;
		if(i < 0) return 1;
		if(i == n) return 2;
	}
	return 0;
}

int32_t main()
{
	ios::sync_with_stdio(0); cin.tie(0);
	cin>> n >> q;
	cin>> s;
	for(int i = 0; i < q; i++)
	{
		char z, y;
		cin>> z >> y;
		t += z;
		x += y;
	}
	int l = -1, r = n;
	while(r - l > 1)
	{
		int mid = (l + r) / 2;
		if(get(mid) == 1) l = mid;
		else r = mid;
	}
	int lo = -1, hi = n;
	while(hi - lo > 1)
	{
		int mid = (hi + lo) / 2;
		if(get(mid) == 2) hi = mid;
		else lo = mid;
	}
	cout<< n - ((l + 1) + (n - hi)) << endl;
}
