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;
typedef long long int ll;
typedef pair<char,char> p2;
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    ll n,q,res=0;
    string s;
    cin>>n>>q>>s;
    vector<p2> v(q);
    for(ll i=0;i<q;i++)
    cin>>v[i].first>>v[i].second;
    ll l=0,r=n-1;
    while(l<=r){
        ll m=(l+r)/2;
        ll pos=m;
        for(ll i=0;i<q;i++)
        if(pos>=0&&pos<n&&s[pos]==v[i].first)
        pos+=(v[i].second=='R'?1:-1);
        if(pos==(-1))
        l=m+1;
        else
        r=m-1;
    }
    res-=r+1;
    l=0;
    r=n-1;
    while(l<=r){
        ll m=(l+r)/2;
        ll pos=m;
        for(ll i=0;i<q;i++)
        if(pos>=0&&pos<n&&s[pos]==v[i].first)
        pos+=(v[i].second=='R'?1:-1);
        if(pos==n)
        r=m-1;
        else
        l=m+1;
    }
    res+=l;
    cout<<res;
}
