#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <ctime>
#include <cmath>
#define ll long long
#define maxn 100020
using namespace std;


ll f[1020][12];
ll ans;
int n,m;
int a[maxn],b[maxn],k[maxn],p[maxn];

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 j=0;j<=10;++j){
      for(int i=0;i<=1001;++i){
        f[i][j]=100001;
        f[i][j]*=1001;
      }
    }

    int mxn = f[0][0];
    for(int j=0;j<=10;++j){
      f[0][j] = 0;
      for(int i=0;i<=1000;++i){
        if(f[i][j] == mxn)continue;
        for(int z=1;z<=m;++z){
          if(p[z] <= j)continue;
          int x = p[z] - j;
          int y = min(i+x,1000);
          f[y][j] = min(f[y][j],f[i][j]+k[z]);
        }
      }
      for(int i=1000;i>=0;--i){
        f[i][j]=min(f[i][j],f[i+1][j]);
      }
    }
    ans = 0;
    for(int i=1;i<=n;++i){
      if(f[a[i]][b[i]] == mxn){
        ans = -1;
        break;
      }
      ans += f[a[i]][b[i]];
    }
    cout<<ans<<endl;
  }
  return 0;
}