#include<iostream>
#include<cstring>
#define  INF 0x3f3f3f3f
using namespace std;
int a[100001],b[100001];
int p[1001],k[1001];
int dp[11][1001];
int main(){
    int n,m;
    long long summin;
    while(scanf("%d%d",&n,&m)!=EOF){
        memset(dp,INF,sizeof(dp));
        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 i=0;i<=10;i++){
            for(int j=1;j<=1000;j++){
                for(int u=1;u<=m;u++){
                    if(p[u]<=i)continue;
                    int y=p[u]-i;
                    if(y>=j)dp[i][j]=min(dp[i][j],k[u]);
                    else dp[i][j]=min(dp[i][j],dp[i][j-y]+k[u]);
                }
            }
        }
        summin=0;
        for(int i=1;i<=n;i++){
            if(dp[b[i]][a[i]]==INF){summin=-1;break;}
            summin+=dp[b[i]][a[i]];
        }
        cout<<summin<<endl;
    }
    return 0;
}