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 LL long long
#define pa pair<int,int>
const int Maxn=200010;
const int inf=2147483647;
int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9')x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
	return x*f;
}
int n,m,a[Maxn],b[Maxn];
char s[Maxn],s1[3],s2[3];
int g(int x)
{
	int p=x;
	for(int i=1;i<=m;i++)
	{
		if(a[i]==s[p]-'A')p+=b[i];
		if(p==0||p==n+1)return p;
	}
	return p;
}
int main()
{
	n=read(),m=read();
	scanf("%s",s+1);
	for(int i=1;i<=m;i++)
	{
		scanf("%s%s",s1,s2);
		a[i]=s1[0]-'A';b[i]=((s2[0]=='L')?-1:1);
	}
	int ans=n;
	int l=1,r=n;
	while(l<=r)
	{
		int mid=l+r>>1;
		if(g(mid)==0)l=mid+1;
		else r=mid-1;
	}
	ans-=(l-1);//printf("%d\n",l-1);
	l=1,r=n;
	while(l<=r)
	{
		int mid=l+r>>1;
		if(g(mid)==n+1)r=mid-1;
		else l=mid+1;
	}
	ans-=(n-r);//printf("%d",r+1);
	printf("%d",ans);
}