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 ll;
const ll N=2e5+5;
string s;
char t[N],d[N];
ll n,q;
ll chk(ll p){
    for(ll i=1;i<=q;i++){
        if(t[i]==s[p]){
            if(d[i]=='L')p--;
            else p++;
            if(p<0 || p>=n)return p;
        }
    }
    return p;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin>>n>>q>>s;
    for(ll i=1;i<=q;i++)cin>>t[i]>>d[i];
    ll ans = n;
    ll s=0,e=n-1;
    while(s<=e){
        ll mid=(s+e)>>1;
        if(chk(mid)<0)s=mid+1;
        else e=mid-1;
    }
    ans-=s;
    s=0,e=n-1;
    while(s<=e){
        ll mid=(s+e)>>1;
        if(chk(mid)>=n)e=mid-1;
        else s=mid+1;
    }
    ans-=(n-1-e);
    cout<<ans;
}