#include <iostream>
#include <stdio.h>
#include <string.h>
#define ll long long
using namespace std;
const int N = 100010;
const int M = 1010;
ll a[N], b[N], p[M], k[M];
ll dp[M][12];
int main() {
    int n, m;
    while(scanf("%d %d", &n, &m) != EOF) {
        ll ans1 = 0, ans2 = 0, ans3 = 0;
        for(int i = 1; i <= n; i ++) {
            cin >> a[i] >> b[i];
            ans1 = max(ans1, a[i]);
            ans2 = max(ans2, b[i]);
        }
        for(int i = 1; i <= m; i ++) {
            cin >> k[i] >> p[i];
            ans3 = max(ans3, p[i]);
        }
        if(ans3 <= ans2) {
            printf("-1\n");
            continue;
        }
        for(int i = 0; i < M; i ++) {
            for(int j = 0; j < 12; j ++) dp[i][j] = 100000000000L;
        }
        for(int i = 0; i < 12; i ++) dp[0][i] = 0;
        for(int i = 1; i <= m; i ++) {
            for(int j = 1; j <= ans1; j ++) {
                for(int l = 0; l < 12; l ++) {
                    if(p[i] <= l) continue;
                    int ans = p[i]-l;
                    if(ans >= j) dp[j][l] = min(dp[j][l], dp[0][l]+k[i]);
                    else dp[j][l] = min(dp[j][l], dp[j-ans][l]+k[i]);
                }
            }
        }
        ll sum = 0;
        for(int i = 1; i <= n; i ++) {
            if(a[i] <= 0) continue;
            sum += dp[a[i]][b[i]];
        }
        printf("%lld\n",sum);
    }
    return 0;
}