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>

using namespace std;

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

    auto f = [&](int p) -> int
    {
        if (p>=N)
            return 1;
        for (int i=0; i<Q; i++)
        {
            if (s[p]==t[i])
                if (d[i]=='L')
                    p--;
                else
                    p++;
            if (p<0)
                return -1;
            if (p>=N)
                return 1;
        }
        return 0;
    };

    int B = 1;
    while (B<N)
        B *= 2;

    int l = -1;
    for (int b=B; b>0; b/=2)
        if (f(l+b)==-1)
            l += b;
    int r = -1;
    for (int b=B; b>0; b/=2)
        if (f(r+b)!=1)
            r += b;
    cout<<r-l<<endl;
}
