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;
#define int long long
const int MOD = 1000000007LL;
const int INF = LLONG_MAX;

signed main(){
    
    int n, q; cin >> n >> q;
    string s; cin >> s;
    vector<char> t(q);
    vector<char> d(q);
    for(int i = 0; i < q; i++) cin >> t[i] >> d[i];

    int l = 0;
    int r = n;
    for(int i = q - 1; i >= 0; i--){

        //cout << l << " " << r << endl;
        if(d[i] == 'R'){
            if(s[r - 1] == t[i]) r--;
            if(l != 0 && s[l - 1] == t[i]) l--;
        }else{
            if(s[l] == t[i]) l++;
            if(r != n && s[r] == t[i]) r++;
        }
    }

    //cout << l << " " << r << endl;
    cout << max(0LL, r - l) << endl;
    return 0;
}