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;
typedef double db;
typedef pair<ll,ll> P;
#define pb push_back
#define ft first
#define sd second
#define mp make_pair
#define fr(i,n) for(int i=0;i<n;i++)
#define Fr(i,n) for(int i=0;i++<n;)
#define ifr(i,n) for(int i=n-1;i>=0;i--)
#define iFr(i,n) for(int i=n;i>0;i--)

ll n,q;
char s[200010],t[200010],d[200010];

bool ok(ll m,bool key){
  fr(i,q){
    if(t[i]==s[m]){
      if(d[i]=='L') m--;
      else m++;
      if(m<0) return 1-key;
      if(m>=n) return key;
    }
  }
  return 0;
}

int main(){
  cin>>n>>q;
  ll ans=n;
  fr(i,n) cin>>s[i];
  fr(i,q) cin>>t[i]>>d[i];
  ll l=-1,r=n,m;
  while(r-l>1){
    m=(l+r)/2;
    if(ok(m,0)) l=m;
    else r=m;
  }
  ans-=l+1;
  l=-1;r=n;
  while(r-l>1){
    m=(l+r)/2;
    if(ok(m,1)) r=m;
    else l=m;
  }
  ans-=n-r;
  cout<<ans<<endl;
}