#include<iostream>
#include<stdio.h>
#include<cstring>
using namespace std;
const long long INF = 999999999999999;

long long a[100001], b[100001];
long long kk[1001], p[1001];
long long dp[1001][11];
int vis[1001][11];
int n, m;

long long dfs(int x, int y)
{
    if(x <= 0){
        return 0;
    }
    
    if(vis[x][y]){
        return dp[x][y];
    }
    
    vis[x][y] = 1;
    
    int i;
    dp[x][y] = INF;
    for(i=0; i<m; i++)
    {
        if(p[i] > y)
        {
            long long cur = dfs(x - (p[i]-y), y);
            if(dp[x][y] > cur + kk[i])
            {
                dp[x][y] = cur + kk[i];
            }
            //cout << x << " " << y << " " << dp[x][y] << " " << i << "   ";
        }
    }
    
    return dp[x][y];
}

int main()
{
    int i, j;
    while(cin >> n >> m)
    {
        memset(vis, 0, sizeof(vis));
        memset(dp, 0, sizeof(dp));
        
        for(i=0; i<n; i++)
        {
            //cin >> a[i] >> b[i];
            scanf("%lld%lld", &a[i], &b[i]);
        }
        
        for(i=0; i<m; i++)
        {
            //cin >> kk[i] >> p[i];
            scanf("%lld%lld", &kk[i], &p[i]);
        }
        
        long long cur = INF;
        //dfs(1000, 5);
        
        
        for(i=0; i<=10; i++)
        {
            //dfs(1000, i);
            for(j=1000; j>=0; j--)
            {
                /*
                if(!vis[j][i])
                {
                    dp[j][i] = cur; 
                }
                else{
                    cur = dp[j][i];
                }*/
                dfs(j, i);
            }
        }
        
        
        long long ans = 0;
        for(i=0; i<n; i++)
        {
            if(dp[a[i]][b[i]] == INF){
                ans = -1;
                break;
            }
            else{
                ans += dp[a[i]][b[i]];
            }
            //printf("%lld\n", ans);
        }
        
        printf("%lld\n", ans);
        //cout << ans << endl;
    }
    
    
    
    return 0;
    
    
}