#include <map>
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <set>
#include <queue>
#include <cstring>
#include <algorithm>
using namespace std;
#define cle(a,v) memset(a,(v),sizeof(a))
#define fo(i,a,b) for(int i=(a);i<=(b);i++)
#define fd(i,a,b) for(int i=(a);i>=(b);i--)
#define ll long long
const int maxn = 100000 + 7, maxm = 1000 + 7;
int n, m;
int a[maxn], b[maxn], k[maxm], p[maxm], dp[11][maxm];
int main() {
    //("1.in", "r", stdin);
    while (~scanf("%d%d", &n, &m)) {
        int topp = 0, topb = 0, topa = 0;
        fo(i, 1, n) {
            scanf("%d%d", &a[i], &b[i]);
            topb = max(b[i], topb);
            topa = max(a[i], topa);
        }
        fo(i, 1, m) {
            scanf("%d%d", &k[i], &p[i]);
            topp = max(p[i], topp);
        }
        if (topp <= topb) {
            puts("-1");
            continue;
        }
        cle(dp, 0x7f);
        for (int i = 0; i <= 10; i++) {
            for (int j = 1; j <= topa; j++) {
                for (int u = 1; u <= m; u++) {
                    int damage = p[u] - i;
                    if (damage < 0) continue;
                    if (j <= damage) dp[i][j] = min(dp[i][j], k[u]);
                    else {
                        dp[i][j] = min(dp[i][j], dp[i][j - damage] + k[u]);
                    }
                }
            }
        }
        ll ans = 0;
        fo(i, 1, n) {
            ans += dp[b[i]][a[i]];
        }
        printf("%I64d\n", ans);
    }
    return 0;
}