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;

int main(){
    long N, Q;
    string s;
    cin >> N >> Q >> s;
    long l = 0, r = N;
    vector<pair<char, long>> v(Q);
    for(auto& i : v){
        char c;
        cin >> i.first >> c;
        i.second = !(c & 2);
    }
    reverse(v.begin(), v.end());
    for(const auto& i : v){
        if(i.second){
            if(s[l] == i.first)++l;
            if(r < N && s[r] == i.first)++r;
        }else{
            if(l && s[l - 1] == i.first)--l;
            if(s[r - 1] == i.first)--r;
        }
    }
    cout << r - l << endl;
    return 0;
}