#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

typedef long long LL;

const int N = 1e5 + 10;
const int M = 1e3 + 10;

int n, m, a[N], b[N], x[N], y[N];

int main() {

    while (scanf("%d %d", &n, &m) != EOF) {
        int mx = 0;
        for (int i = 1; i <= n; ++i) {
            scanf("%d %d", &a[i], &b[i]);
            mx = max(mx, a[i]);
        }
        for (int i = 1; i <= m; ++i)
            scanf("%d %d", &x[i], &y[i]);

        static LL g[N];
        for (int _b = 0; _b <= 10; ++_b) {
            static LL f[M];
            for (int i = 1; i <= mx; ++i)
                f[i] = -1;
            f[0] = 0;
            for (int i = 1; i <= mx; ++i) {
                LL nf = -1;
                for (int j = 1; j <= m; ++j) {
                    if (y[j] > _b) {
                        LL tf = f[max(0, i - (y[j] - _b))] + x[j];
                        if (nf == -1 || nf > tf)
                            nf = tf;
                    }
                }
                f[i] = nf;
            }
            for (int i = 1; i <= n; ++i)
                if (b[i] == _b)
                    g[i] = f[a[i]];
        }
        bool ok = 1;
        LL sum = 0;
        for (int i = 1; i <= n; ++i) {
            if (~g[i])
                sum += g[i];
            else
                ok = 0;
        }
        if (!ok)
            puts("-1");
        else
            cout << sum << endl;
    }

    return 0;
}