#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define sz size
#define ll long long
#define ld long double
#define fs first
#define sc second
#define forn(i, f, t) for(int i = f; i < t; i++)
#define all(x) (x).begin(), (x).end()
#define ins insert

const int INF = 2147483647;
const int MOD = 1000000007;
const ll INF64 = 9223372036854775807;
const ld EPS = 1e-7;

using namespace std;


int main(){
    int n, m, k, t, ans = 0;
    string ph, s;
    vector<pair<int, string> > phs;
    cin >> m >> n;
    cin >> s;
    forn(i, 0, n){
        cin >> k >> t;
        cin >> ph;
        phs.pb(mp(t, ph));
    }
    sort(all(phs));
    int cnt = 0;
    forn(i, 0, n)
        forn(j, 0, phs[i].sc.sz())
            forn(k, 0, m)
                if (s[k] == phs[i].sc[j]){
                    s[k] = '0';
                    ans += phs[i].fs;
                    cnt++;
                }
    cout << (cnt == m ? ans : -1) << "\n";
    return 0;
}