#include <bits/stdc++.h>

using namespace std;

const int INF = 0x3f3f3f3f;

int a[100005], b[100005], p[1005], k[1005];
int dp[11][1010];


int main() {
    int n, m;
    while(~scanf("%d%d", &n, &m)) {
        for(int i = 1; i <= n; i++) {
            scanf("%d%d", &a[i], &b[i]);
        }
        for(int i = 1; i <= m; i++) {
            scanf("%d%d", &k[i], &p[i]);
        }
        for(int defence = 0; defence <= 10; defence++) {
            dp[defence][0] = 0;
            for(int power = 1; power <= 1000; power++) {
                dp[defence][power] = INF;
            }

        }
        for(int defence = 0; defence <= 10; defence++) {
            for(int i = 1; i <= m; i++) {
                for(int power = 0; power <= 1000; power++) {
                    if(p[i] > defence)  {
                        int lost = max(power + defence - p[i], 0);
                        dp[defence][power] = min(dp[defence][power], dp[defence][lost] + k[i]);
                    }
                }
            }
        }
        int flag = 0;
        long long int ans = 0;
        for(int i = 1; i <= n; i++) {
            if(dp[b[i]][a[i]] == INF) {
                flag = 1;
                break;
            }
            ans += dp[b[i]][a[i]];
        }
        if(flag) printf("-1\n");
        else printf("%lld\n", ans);
    }
    return 0;
}