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>
#define FOR(i,a,n) for(ll i=(ll)a;i<(ll)n;i++)
#define rep(i,n) FOR(i,0,n)
using namespace std;
typedef long long ll;

ll n,q;
string s;
vector<char> t,d;

int f(ll x){
    if(x<0)return -1;
    if(n<=x)return 1;
    rep(i,q){
        if(t[i]==s[x]){
            x+=(d[i]=='R'?1:-1);
        }
        if(x==-1)return -1;
        if(x==n)return 1;
    }
    return 0;
}

int main(){
    cin>>n>>q>>s;
    t.resize(q);
    d.resize(q);
    rep(i,q)cin>>t[i]>>d[i];
    ll l=-1,r=n;
    while(l<r-1){
        ll mid=(r+l)/2;
        if(f(mid)==-1)l=mid;
        else r=mid;
    }
    ll num=r;
    l=-1; r=n;
    while(l+1<r){
        ll mid=(l+r)/2;
        if(f(mid)==1)r=mid;
        else l=mid;
    }
    cout<<r-num<<endl;
}