#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)

const double EPS = 1e-9;
const int MOD = 1e9+7;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

void DBG(){cout << "]" << endl;}
template<typename T, typename ...U> void DBG(const T& head, const U... args){ cout << head << "; "; DBG(args...); }
#define dbg(...) cout << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
#define chk() cout << "Check at line(" << __LINE__ << ") hit." << endl;

template<class T, unsigned int U>
ostream& operator<<(ostream& out, const array<T, U> &v){out << "[";  REP(i, U) out << v[i] << ", ";  out << "]"; return out;}
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}

template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());


int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    int h, t;
    cin >> h >> t;
    vector<int> c(h);
    cin >> c;
    vector<int> d(t), in(t);
    REP(i, t){
        cin >> d[i] >> in[i];
    }
    vector<int> su((1 << t), 0);
    REP(mask, (1 << t)){
        REP(j, t){
            if(mask & (1 << j))
                su[mask] += d[j];
        }
    }
    const int mx = 17;
    vector<vector<int>> dp(mx + 1, vector<int>((1 << t), 0));
    dp[0][0] = 1;
    REP(i, mx){
        vector<int> intervals;
        int curr = 0;
        REP(j, h){
            if(c[j] > i){
                curr++;
            }
            else{
                if(curr > 0){
                    intervals.pb(curr);
                }
                curr = 0;
            }
        }

        if(curr > 0)
            intervals.pb(curr);
        sort(all(intervals), greater<int>());
        if(intervals.size() == 0){
            REP(mask, (1 << t)){
                if(dp[i][mask])
                    dp[i + 1][mask] = 1;
            }
            continue;
        }
        if(intervals.size() > mx){
            cout << 0 << "\n";
            return 0;
        }
        vector<vector<int>> ndp(intervals.size() + 1, vector<int>((1 << t), 0));
        ndp[0][0] = 1;
        FOR(j, 1, intervals.size() + 1, 1){
            REP(mask, (1 << t)){
                for(int s = mask; s > 0; s = (s - 1) & mask){
                    if(su[s] == intervals[j - 1] && ndp[j - 1][mask&(~s)]){
                        ndp[j][mask] = 1;
                        break;
                    }
                }
            }
        }
        bool fn = false;
        REP(mask, (1 << t)){
            for(int s = mask; s > 0; s = (s - 1) & mask){
                if(ndp[intervals.size()][s] && dp[i][mask&(~s)]) {
                    dp[i + 1][mask] = 1;
                    fn = true;
                    break;
                }
            }
        }
        if(!fn){
            cout << 0 << "\n";
            return 0;
        }
    }
    int ans = 0;
    REP(mask, (1 << t)){
        if(dp[mx][mask]){
            int tm = 0;
            REP(j, t){
                if(mask & (1 << j)){
                    tm += in[j];
                }
            }
            ans = max(ans, tm);
        }
    }
    cout << ans << "\n";
    return 0;
}