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;
int n,q;
char a[200005],b[200005];
string s;
int sol(int x,int u)
{
    x--;
    for(int i=1;i<=q;i++)
        if(a[i]==s[x])
    {
        if(b[i]=='L')
        {
            x--;
            if(x<0&&!u) return 1;
        }
        else
        {
            x++;
            if(x==n&&u) return 1;
        }
    }
    return 0;
}
int main()
{
    cin>>n>>q;
    cin>>s;
    for(int j=1;j<=q;j++)
        cin>>a[j]>>b[j];
    int rez=n+1,rez1=0;
    for(int step=1<<17;step;step>>=1)
        if(rez-step>=0&&sol(rez-step,1)) rez-=step;
    for(int step=1<<17;step;step>>=1)
        if(rez1+step<=n&&sol(rez1+step,0)) rez1+=step;
    if(rez>rez1)
    cout<<rez-rez1-1;
    else cout<<0;
}
