#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int n,m,a[100005],b[100005],k[1005],p[1005];
long long ans,dp[15][1005];
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",&k[i],&p[i]);
        memset(dp,0x3f,sizeof(dp));
        long long INF=dp[0][0];
        for(int fy=0;fy<=10;fy++) dp[fy][0]=0;
        for(int fy=0;fy<=10;fy++)
            for(int hp=1;hp<=1000;hp++)
                for(int jn=1;jn<=m;jn++)
                {
                    if(p[jn]<=fy) continue;
                    if(hp-(p[jn]-fy)<0) dp[fy][hp]=min(dp[fy][hp],(long long)k[jn]);
                    else dp[fy][hp]=min(dp[fy][hp],dp[fy][hp-(p[jn]-fy)]+k[jn]);
                }
        bool flag=true;
        ans=0;
        for(int i=1;i<=n;i++)
        {
            if(dp[b[i]][a[i]]==INF){flag=false;break;}
            ans+=dp[b[i]][a[i]];
        }
        if(flag) printf("%lld\n",ans);
        else puts("-1");
    }
    return 0;
}