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;
const int N=2e5+5,YL=1e9+7;
inline int MO(const int &x){return x>=YL?x-YL:x;}
inline int in(){int k;cin>>k;return k;}
inline int low(int x){return x&(-x);}
char s[N],a[N],b[N];int n,m;
typedef std::pair<int,int> P;
#define mk make_pair
inline void add(int &x,int y){if((x+=y)>=YL)x-=YL;}
int check(int mid)
{
	int p=mid;
	for(int i=1;i<=m;++i)
		if(s[p]==a[i])
		{
			p+=b[i]=='L'?-1:1;
			if(!p)return -1;
			else if(p>n)return 1;
		}
	return 0;
}
int main()
{
	ios::sync_with_stdio(0);
	cin>>n>>m>>s+1;
	for(int i=1;i<=m;++i)cin>>a[i]>>b[i];
	int l=1,r=n,ans=0;
	while(l<=r)
	{
		int mid=l+r>>1;
		if(check(mid)==-1)ans=mid,l=mid+1;
		else r=mid-1;
	}
	int res=n-ans;l=1,r=n,ans=n+1;
	while(l<=r)
	{
		int mid=l+r>>1;
		if(check(mid)== 1)ans=mid,r=mid-1;
		else l=mid+1;
	}
	res-=n-ans+1;printf("%d\n",res);
	return 0;
}
