1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cctype>
 5 #include<cmath>
 6 #include<cstring>
 7 #include<map>
 8 #include<set>
 9 #include<queue>
10 #include<vector>
11 #include<algorithm>
12 #include<string>
13 #define ll long long
14 #define eps 1e-10
15 #define LL unsigned long long
16 using namespace std;
17 const int INF=0x3f3f3f3f;
18 const int N=100000+100;
19 const int mod=998244353;
20 int a[N],b[N];
21 struct node{
22     int k,p;
23 }val[N];
24 ll dp[1010][20];
25 ll minn[N];
26 bool cmp(node a,node b)
27 {
28     return a.k-a.p<b.k-b.p;
29 }
30 int main()
31 {
32     int n,m;
33     while(scanf("%d%d",&n,&m)!=EOF)
34     {
35         int maxx1=0;
36         int maxx2=0;
37         memset(minn,INF,sizeof(minn));
38         for(int i=0;i<n;i++){
39           scanf("%d%d",&a[i],&b[i]);
40           maxx1=max(maxx1,b[i]);
41         }
42         for(int i=0;i<m;i++){
43           scanf("%d%d",&val[i].k,&val[i].p);
44           maxx2=max(maxx2,val[i].p);
45         }
46         for(int i=0;i<1010;i++)
47         for(int j=0;j<20;j++)dp[i][j]=1e10;
48         for(int j=0;j<=10;j++)dp[0][j]=0;
49         sort(val,val+m,cmp);
50         for(int k=0;k<=10;k++)
51         for(int i=0;i<m;i++)
52         for(int j=1;j<=1000;j++){
53             if(j-val[i].p+k<=0)dp[j][k]=min((ll)val[i].k,dp[j][k]);
54            else
55             dp[j][k]=min(dp[j][k],dp[j-val[i].p+k][k]+val[i].k);
56 
57         }
58         ll ans=0;
59         for(int i=0;i<n;i++){
60             ans=ans+dp[a[i]][b[i]];
61         }
62         if(maxx2<=maxx1)cout<<-1<<endl;
63         else
64             printf("%I64d\n",ans);
65     }
66     return 0;
67 }