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;
char x[200010],y[200010];
long n,q,c=-1,d;
string s;
int main()
{
    ios::sync_with_stdio(false);
    cin>>n>>q>>s;
    d=n;
    for(int i=0; i<q; i++)
        cin>>x[i]>>y[i];
    for(int i=q-1; i>=0; i--)
    {
        if(x[i]==s[c+1]&&y[i]=='L')
            c++;
        if(x[i]==s[d-1]&&y[i]=='R')
            d--;
        if(x[i]==s[c]&&y[i]=='R')
            c--;
        if(x[i]==s[d]&&y[i]=='L')
            d++;
    }
    cout<<max(0,(int)(d-c-1))<<endl;
    return 0;
}
