1003a.cpp

/*************************************************************************
	> File Name: 1003a.cpp
	> Author: heheql
	> Mail: 374655767@qq.com
	> Created Time: 2017年08月06日 星期日 19时41分24秒
 ************************************************************************/

#include <iostream>
using namespace std;
const int maxn = 1e9;
int main(){
	freopen("input.txt","r",stdin);
	ios::sync_with_stdio(false);
    int n, m;
    while(cin >> n >> m){
        int a[n], b[n];
        int k[m], p[m];
        int maxhp = -1;
        int max1 = -1;
        int max2 = -1;
        for(int i = 0; i < n; i++){
            cin >> a[i] >> b[i];
            maxhp = max (maxhp, a[i]);
            max1 = max (max1, b[i]);
        }
        for(int i = 0; i < m; i++){
            cin >> k[i] >> p[i];
            max2 = max (max2, p[i]);
        }
        if(max2 <= max1){
            cout<<-1<<endl;
            continue;
        }
        int dp[1010][1010] = {0};
        for(int i=0;i<=10;i++){
            for(int j=0;j<=maxhp;j++){
                dp[j][i]=maxn;
                for(int kk=0;kk<m;kk++){
                    int temp = p[kk] - i;
                    if(temp<=0){
                        continue;
                    }
                    if(temp<j){
                        dp[j][i]=min(dp[j][i],dp[j-temp][i]+k[kk]);
                    }else{
                        dp[j][i]=min(dp[j][i],k[kk]);
                    }
                }
            }
        }
        long long sum=0;
        for(int i=0;i<n;i++){
            sum+=dp[a[i]][b[i]];
        }
        cout<<sum<<endl;
    }
	return 0;
}