#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<cmath>
#include<map>
#define ll long long 
using namespace std;
const int maxn=500010,inf=2e9;
ll n,m,x,y,z,tot;
ll a[maxn],b[maxn],K[maxn],p[maxn];    
ll ans,f[20][2010];
void read(ll &k)
{
    int f=1;k=0;char c=getchar();
    while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar();
    while(c<='9'&&c>='0')k=k*10+c-'0',c=getchar();
    k*=f;
}
int main()
{
    while(scanf("%I64d%I64d",&n,&m)==2)
    {
        for(int i=1;i<=n;i++)read(a[i]),read(b[i]);
        for(int i=1;i<=m;i++)read(K[i]),read(p[i]);
        memset(f,0x3f,sizeof(f));
        for(int i=0;i<=10;i++)f[i][0]=0;
        for(int k=1;k<=m;k++)
        for(int i=0;i<=10;i++)
        {
            int damage=p[k]-i;
            for(int j=0;j<=1000;j++)
            f[i][j]=min(f[i][j],f[i][max(0,j-damage)]+K[k]);
        }
        ans=0;bool flag=0;
        for(int i=1;i<=n;i++)
        {
            ans+=f[b[i]][a[i]];
            if(f[b[i]][a[i]]>=inf)
            {
                flag=1;
                break;
            }
        }
        printf("%I64d\n",flag?-1:ans);
    }
    return 0;
}