#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#define rep(i,a,b) for (int i=(a),_ed=(b);i<=_ed;++i)
using namespace std;
typedef long long ll;
const int N=100100;
const int M=1010;
int n,m;
ll a[N],b[N],k[M],p[M],f[M][12];
int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        ll maxb=0,maxa=0;
        rep(i,0,n-1)
        {
            scanf("%I64d%I64d",a+i,b+i);
            maxa=max(maxa,a[i]);
            maxb=max(maxb,b[i]);
        }
        ll maxp=0;
        rep(i,0,m-1)
        {
            scanf("%I64d%I64d",k+i,p+i);
            maxp=max(maxp,p[i]);
        }
        if (maxb>=maxp)
        {
            puts("-1");
            continue;
        }
        memset(f,127,sizeof(f));
        rep(i,0,10)f[0][i]=0;
        rep(i,0,10)
            rep(j,1,maxa)
                rep(l,0,m-1)
                    if(p[l]-i>=j)
                    f[j][i]=min(f[j][i],k[l]);
                    else if(p[l]-i>0)
                    f[j][i]=min(f[j][i],f[j-(p[l]-i)][i]+k[l]);
        ll ans=0;
        rep(i,0,n)ans+=f[a[i]][b[i]];
        printf("%I64d\n",ans);
    }
    return 0;
}