#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define FOR(i, j, k) for(int i = j;i<=k;i++)
#define ll long long
int a[100010];
int b[100010];
int k[1010],p[1010];
ll dp[2010][15];
int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m)){
        FOR(i, 1, n)
            scanf("%d%d",&a[i],&b[i]);
        FOR(i, 1, m)
            scanf("%d%d",&k[i],&p[i]);
        FOR(i, 0, 2000)
            FOR(j, 0, 10){
                if(i == 0) dp[0][j] = 0;
                else
                    dp[i][j] = 1e18;
            }
        FOR(i, 0,10)
        {
            FOR(j, 1,m)
            {
                int t = p[j] -i;
                if(t < 0) continue;
                FOR(x, t, 2000)
                    dp[x][i]=min(dp[x][i], dp[x-t][i]+ (ll)k[j]);
            }
            //cout<<dp[1000][i]<<endl;
            for(int x = 1999;x >=0 ;x--)
                dp[x][i]=min(dp[x][i],dp[x+1][i]);
            //FOR(j,0,1000) cout<<dp[j][i]<<" ";
           // cout<<endl;
        }
        ll ans = 0;
        FOR(i, 1, n)
            ans += dp[a[i]][b[i]];
        if(ans >= 1e18)
            cout<<"-1"<<endl;
        else cout<<ans<<endl;
    }
    return 0;
}