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>
#include <string>
#include <vector>
using namespace std;

int N, Q;
string s;
vector<char> t, d;

int C(int x, const bool dir_flag){
    for(int i = 0; i < Q; ++i){
        if(x < 0 || x >= N) break;

        if(s[x] == t[i] && d[i] == 'R') ++x;
        else if(s[x] == t[i] && d[i] == 'L') --x;
    }
    
    if(x < 0) return dir_flag;
    else if(x >= N) return !dir_flag;
    else return false;
}

int main(){
    cin >> N >> Q;
    cin >> s;

    t.resize(Q);
    d.resize(Q);
    for(int i = 0; i < Q; ++i) cin >> t[i] >> d[i];

    int ans = N;

    int lb = -1, ub = N+1, mid;
    while(ub - lb > 1){
        mid = (lb+ub)/2;
        if(C(mid, true)) lb = mid;
        else ub = mid;
    }

    ans -= ub;

    lb = -1;
    ub = N+1;
    while(ub - lb > 1){
        mid = (lb+ub)/2;
        if(C(mid, false)) ub = mid;
        else lb = mid;
    }
    ans -= N-ub;

    cout << ans << endl;
}