#include <bits/stdc++.h>
using namespace std;
const int maxn=100005;
const int maxm=1005;
const long long inf=0x3f3f3f3f3f3f3f3f;
int n,m,a[maxn],b[maxn],K[maxm],p[maxm],dp[maxm<<1][11];
int main()
{
    while (scanf("%d%d",&n,&m)==2) {
        for (int i=0;i<n;++i)
            scanf("%d%d",&a[i],&b[i]);
        for (int i=0;i<m;++i)
            scanf("%d%d",&K[i],&p[i]);
        memset(dp,0x3f,sizeof dp);
        for (int i=0;i<=10;++i)
            dp[0][i]=0;
        for (int k=0;k<=10;++k)
            for (int i=0;i<m;++i) if (p[i]>k)
                for (int j=1;j<=2000;++j)
                    dp[j][k]=min(dp[j][k],K[i]+dp[max(0,j-p[i]+k)][k]);
        long long res=0;
        for (int i=0;i<n;++i)
            if (dp[a[i]][b[i]]==0x3f3f3f3f)
                res=inf;
            else
                res+=1LL*dp[a[i]][b[i]];
        printf("%I64d\n",res>=inf?-1:res);
    }
    return 0;
}