#include <bits/stdc++.h>
#define REP(i, x, n) for (int i = (x); i < (n); i++)
#define endl "\n"
#define MAXN 1000000
#define MOD 1000000007
#define inf 10000000000000
typedef long long ll;
using namespace std;
ll maxb, a, b, k, p, ans, n, m;
vector<ll> q[100];
ll maxx[300];
ll cost[3000];
ll v[3000];
ll f[3000];
int main() {
    ios::sync_with_stdio(0);
    while (cin >> n >> m) {
        bool fflg = false;
        ans = 0;
        REP(i, 0, 11) {
            q[i].clear();
        }
        REP(i, 0, n) {
            cin >> a >> b;
            q[b].push_back(a);
            maxx[b] = max(maxx[b], a);
        }
        REP(i, 0, m) {
            cin >> v[i] >> cost[i];
        }
        REP(i, 0, 11) {
            for (int pp = 0; pp < 2500; pp++) f[pp] = inf;
            f[0] = 0;
            REP(k, 0, m) {
                if (cost[k] >= i) {
                    REP(j, 0, maxx[i] * 2) {
                        if (j - cost[k] + i >= 0) {
                            f[j] = min(f[j], f[j - cost[k] + i] + v[k]);
                        }
                    }
                }
            }

            ll minn = inf;
            for (int l = maxx[i] * 2 - 2; l >= 0; l--) {
                if (f[l] != inf) {
                    minn = min(f[l], minn);
                    f[l] = minn;
                } else {
                    f[l] = minn;
                }
            }
            REP(j, 0, q[i].size()) {
                // cout << "q[i][j]=" << q[i][j] << endl;
                if (f[q[i][j]] != inf) {
                    ans += f[q[i][j]];
                } else {
                    fflg = true;
                    break;
                }
            }
            if (fflg) {
                cout << -1 << endl;
                break;
            }
        }
        if (!fflg) cout << ans << endl;
    }
    return 0;
}