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 <vector>
#include <string>
#include <algorithm>

using namespace std;

int solve(const string& S, const vector<pair<char, int>>& query){
    int L = -1, R = S.size();
    while(R-L > 1){
        int mid = (L+R)/2;
        int pos = mid;
        for(auto& q : query){
            if(S[pos] != q.first) continue;
            pos += q.second;
            if(pos < 0 || S.size() <= pos) break;
        }
        if(pos < 0) L = mid;
        else R = mid;
    }
    return L + 1;
}

int main(){
    int N, Q; cin >> N >> Q;
    string s; cin >> s;
    vector<pair<char, int>> query;
    for(int i=0;i<Q;i++){
        string t, d; cin >> t >> d;
        query.emplace_back(t[0], d[0]=='R'?1:-1);
    }
    int res = N - solve(s, query);
    reverse(s.begin(), s.end());
    for(auto& q : query) q.second = -q.second;
    res -= solve(s, query);
    cout << res << endl;
}