#include <bits/stdc++.h>
using namespace std;

int main(int argc, char **argv) {
    ios::sync_with_stdio(false), cin.tie(nullptr);

    int n, m;

    while (cin >> n >> m) {
        vector<int> hp(n), defense(n);

        for (int i = 0; i < n; i++) {
            cin >> hp[i] >> defense[i];
        }

        vector<int> cost(m), damage(m);

        for (int i = 0; i < m; i++) {
            cin >> cost[i] >> damage[i];
        }

        int max_hp = *max_element(hp.begin(), hp.end());

        vector<vector<int64_t>> dp(11, vector<int64_t>(max_hp + 1, 1ll << 50));

        for (int i = 0; i <= 10; i++) {
            dp[i][0] = 0;

            for (int j = 0; j < m; j++) {
                if (damage[j] < i) {
                    continue;
                }
                for (int k = 0; k < max_hp; k++) {
                    int pos = min(max_hp, k + damage[j] - i);
                    dp[i][pos] = min(dp[i][pos], dp[i][k] + cost[j]);
                }
            }

            for (int j = max_hp - 1; j >= 0; j--) {
                dp[i][j] = min(dp[i][j], dp[i][j + 1]);
            }
        }

        int64_t ans = 0;

        for (int i = 0; i < n; i++) {
            if (dp[defense[i]][hp[i]] == (1ll << 50)) {
                ans = -1;
                break;
            } else {
                ans += dp[defense[i]][hp[i]];
            }
        }

        cout << ans << "\n";
    }
}