#include <stdio.h>
#include <iostream>

using namespace std;
#define MAX 1000000000+1
struct monster {
    int a;
    int b;
} MO[100005];
struct jn {
    int k;
    int p;
} JN[2010];
int f[2010][15];

int main() {
    //freopen("in.txt", "r", stdin);
    int n, m;
    while (cin >> n >> m) {
        for (int i = 1; i <= n; i++) {
            scanf("%d%d", &MO[i].a, &MO[i].b);
        }
        for (int i = 0; i < m; i++) {
            scanf("%d%d", &JN[i].k, &JN[i].p);
        }
        long long ans = 0;
        //memset(f,INF,sizeof(f));
        for (int fangyu = 0; fangyu <= 10; fangyu++) {
            f[0][fangyu] = 0;
            for (int i = 1; i <= 2000; i++) {
                f[i][fangyu] = MAX;
            }
        }
        int flag;
        for (int i = 0; i < m; i++)
            for (int fangyu = 0; fangyu <= 10; fangyu++) {
                flag = 1;
                for (int j = JN[i].p - fangyu; j <=2000; j++) {

                    if (JN[i].p > fangyu)
                        f[j][fangyu] =
                                f[j][fangyu]
                                        < f[j - (JN[i].p - fangyu)][fangyu]
                                                + JN[i].k ?
                                        f[j][fangyu] :
                                        f[j - (JN[i].p - fangyu)][fangyu]
                                                + JN[i].k;
                    else {
                        flag = 0;
                        break;
                    }
                }
                if (flag == 0)
                    break;
            }
        for (int fangyu = 0; fangyu <= 10; fangyu++)
            for (int i = 1999; i >= 1; i--) {
                f[i][fangyu] =min( f[i][fangyu], f[i+1][fangyu]);
            }

        for (int i = 1; i <= n; i++) {
            int temp = f[MO[i].a][MO[i].b];
            if (temp == MAX) {
                ans = -1;
                break;
            } else {
                ans += temp;
            }

        }
        cout << ans << endl;
    }
    return 0;
}