#define _CRT_SECURE_NO_DEPRECATE
#include<iostream>
#include<algorithm>
#include<set>
#include<vector>
#include<queue>
#include<cmath>
#include<cstring>
#include<string>
#include<functional>
using namespace std;
#define INF 0x3f3f3f3f
typedef long long ll;
const int N_MAX = 100000 + 5,M_MAX=1000+5,a_MAX=1000+1,b_MAX=10+5;

int n, m;
struct mons {
    int a, b;
    mons(int a=0,int b=0):a(a),b(b) {}
}monster[N_MAX];
int k[M_MAX], p[M_MAX];
int dp[a_MAX][b_MAX];//血量为i防御为j的怪兽需要花费的最少晶石数量

void complete_bag(int k,int p) {
    for (int b = 0; b <=10;b++) {
        if (b >= p)continue;
        int d = p - b;//造成的伤害
        //血量低于伤害时
        for (int a = 1; a <= d; a++) {
            dp[a][b] = min(dp[a][b],k);
        }
        //血量高于伤害时
        for (int a = d + 1; a <= 1000;a++) {
            dp[a][b] = min(dp[a][b],dp[a-d][b]+k);//!!!
        }
    }
}


int main() {
    while (scanf("%d%d",&n,&m)!=EOF) {
        bool flag = 1;
        int best_b=0;
        for (int i = 0; i < n;i++) {
            scanf("%d%d",&monster[i].a,&monster[i].b);
            best_b = max(best_b, monster[i].b);
        }
        for (int i = 0; i < m;i++) {
            scanf("%d%d",&k[i],&p[i]);
            if (best_b < p[i])flag = 0;
        }
        if (flag) { printf("-1\n"); continue; }
        
        for (int i = 0; i <= 1000;i++) {
            for (int j = 0; j <= 10;j++) {
                if (i == 0)dp[i][j] = 0;
                else dp[i][j] = INF;
            }
        }
        
        for (int i = 0; i < m;i++) {//一共m种技能
            complete_bag(k[i], p[i]);
        }
        
        ll res = 0;
        for (int i = 0; i < n;i++) {
            res += dp[monster[i].a][monster[i].b];
            
        }
        printf("%lld\n",res);
    }
    return 0;
}