#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=100010; 
const int M=1010;
const int INF=1061109567;
int a[N],b[N],w[M],p[M],n,m;
int dp[11][M];
int main(){
    while (scanf("%d%d",&n,&m) != EOF){
        for (int i=1; i<=n; i++) scanf("%d%d",&a[i],&b[i]);
        for (int i=1; i<=m; i++) scanf("%d%d",&w[i],&p[i]);
        memset(dp,63,sizeof(dp));
        for (int i=0; i<=10; i++){
            dp[i][0]=0;
            for (int j=1; j<=m; j++)
                if (p[j]>i)
                    for (int k=1; k<=1000; k++) dp[i][k]=min(dp[i][k],dp[i][max(0,k-p[j]+i)]+w[j]);
        }
        long long ans=0;
        for (int i=1; i<=n; i++) 
            if (dp[b[i]][a[i]]==INF){ans=-1; break;}
            else ans+=dp[b[i]][a[i]];
        
        printf("%lld\n",ans);
    }
    return 0;
}