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>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cmath>
#include <iomanip>
using namespace std;

int main() {
    int N, Q; cin >> N >> Q;
    string S; cin >> S;
    vector<pair<char, char>> v(Q);
    for(int i=0; i<Q; ++i){
        char t, d; cin >> t >> d;
        v[Q-i-1]=make_pair(t, d);
    }
    int le=-1, ri=N;
    for(int i=0; i<Q; ++i){
        if(le<N) if(S[le+1]==v[i].first && v[i].second=='L') ++le;
        if(le>-1) if(S[le]==v[i].first && v[i].second=='R') --le;
        if(ri<N) if(S[ri]==v[i].first && v[i].second=='L') ++ri;
        if(ri>0) if(S[ri-1]==v[i].first && v[i].second=='R') --ri;
    }
    cout << max(0, ri-le-1) << endl;
    return 0;
}
