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 <iostream>
using namespace std;
typedef long long ll;
char A[200000],B[200000];
ll n,k,s,g,m,ans;
string t;
bool f(ll p,ll q){
    for(int i=0;i<k;i++){
        if(A[i]==t[p]){
            if(B[i]=='L')p--;
            else p++;
        }
    }
    if(p==q)return true;
    return false;
}
int main(void){
    cin>>n>>k>>t;
    t='#'+t+'#';
    for(int i=0;i<k;i++)cin>>A[i]>>B[i];
    s=0,g=n+1;
    while(g-s>1){
        m=(g+s)/2;
        if(f(m,0))s=m;
        else g=m;
    }
    ans+=s;
    s=0,g=n+1;
    //cout<<ans<<endl;
    while(g-s>1){
        m=(g+s)/2;
        if(f(m,n+1))g=m;
        else s=m;
        //cout<<s<<g<<endl;
    }
    ans+=n-s;
    //cout<<ans<<endl;
    cout<<n-ans<<endl;
}
