#include<set>
#include<map>
#include<deque>
#include<queue>
#include<stack>
#include<cmath>
#include<ctime>
#include<bitset>
#include<string>
#include<vector>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<complex>
#include<iostream>
#include<algorithm>
#define ll long long
#define inf 1e10
using namespace std;

inline void down(ll &x,const ll y){if(x>y)x=y;}
const int maxn = 110000;
const int maxm = 1100;
const int maxa = 1100;
const int maxb = 11;

int n,m;
int a[maxn],b[maxn];
int k[maxn],p[maxn];

ll f[maxb][maxa];

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]);
        
        for(int i=0;i<=10;i++)
        {
            f[i][0]=0; for(int j=1;j<=1000;j++) f[i][j]=inf;
            for(int j=1;j<=m;j++) if(p[j]>i)
            {
                int tmp=p[j]-i;
                for(int l=1;l<=tmp;l++) down(f[i][l],k[j]);
                for(int l=0;l+tmp<=1000;l++) if(f[i][l]!=inf)
                    down(f[i][l+tmp],f[i][l]+k[j]);
            }
        }
        ll ans=0;
        for(int i=1;i<=n;i++) 
        {
            if(f[b[i]][a[i]]==inf) { ans=-1; break; }
            ans+=(ll)f[b[i]][a[i]];
        }
        printf("%I64d\n",ans);
    }
    
    return 0;
}