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>
#define int long long
#define P pair<int,int>
#define inf (int)(3e18)
#define mod (int)(1e9+7)
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;

int n,q;
string s;
char t[222222],d[222222];
signed main(){
	cin>>n>>q>>s;
	rep(i,q)cin>>t[i]>>d[i];
	int le=-1,ri=n;
	for(int i=q-1;i>=0;i--){
		if(s[le+1]==t[i]&&d[i]=='L')le++;
		if(s[ri-1]==t[i]&&d[i]=='R')ri--;
		if(le!=-1&&s[le]==t[i]&&d[i]=='R')le--;
		if(ri!=n&&s[ri]==t[i]&&d[i]=='L')ri++;
	}
	cout<<max(0ll,ri-le-1)<<endl;
}
