#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T>& V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> >& Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T>& mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }
template<typename T>vector<T> make_v(size_t a){return vector<T>(a);}
template<typename T,typename... Ts>auto make_v(size_t a,Ts... ts){return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type fill_v(T &t,const V &v){t=v;}
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type fill_v(T &t,const V &v){for(auto &e:t) fill_v(e,v);}
/*
 <url:>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */


template<class Type>
Type solve(Type res = Type()){
    int N,Q; cin >> N >> Q;
    string s; cin >> s;
    for(auto& c:s) c -= 'A';

    vector<set<int>> G(26);
    vector<int> C(N,1);
    for(int i = 0; i < N;i++){
        G[s[i]].insert(i);
    }

    for(int i = 0; i < Q;i++){
        char t,d; cin >> t >> d;
        t -= 'A';
        
        if(d == 'L'){
            vector<pii> add;
            for(auto it = G[t].begin(); it != G[t].end(); it++){
                int T = C[*it];
                C[*it] = 0;
                if(*it == 0) continue;
                add.push_back({*it,T});
            }
            G[t].clear();
            
            
            for(auto p:add){
                int idx = p.first-1;
                G[s[idx]].insert(p.first-1);
                C[p.first-1] += p.second;
            }
        }
        if(d == 'R'){
            vector<pii> add;
            for(auto it = G[t].rbegin(); it != G[t].rend(); it++){
                int T = C[*it];
                C[*it] = 0;
                if(*it == N-1) continue;
                add.push_back({*it,T});
            }
            G[t].clear();
            
            
            for(auto p:add){
                int idx = p.first+1;
                G[s[idx]].insert(p.first+1);
                C[p.first+1] += p.second;
            }
        }
    }
    res = accumulate(C.begin(),C.end(),0);
    return res;
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    // solve(0);
    cout << fixed << setprecision(15) << solve<ll>() << endl;
    return 0;
}
