#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
using namespace std;

typedef long long ll;
const int N = 1e5 + 5;
int a[N], b[N];
int k[1005], p[1005];
int dp[11][2005];

int main()
{
    int n,m;
    while(cin>>n>>m)
    {
        for(int i = 0; i < n ; i++)
            scanf("%d%d",&a[i], &b[i]);
        for(int i = 0; i < m; i++)
            scanf("%d%d",&k[i], &p[i]);
        memset(dp, -1, sizeof(dp));
        for(int i = 0; i <= 10; i++)
        {
            dp[i][0] = 0;
            for(int o = 0; o < m; o++)
            {
                int gap = p[o] - i;
                if(gap > 0)
                {
                    for(int j = 0; j < gap; j++)
                    {
                        if( -1 != dp[i][j])
                        {
                            int cur = j + gap;
                            while( cur < 2000 )
                            {
                                if( -1 == dp[i][cur] || dp[i][cur - gap] + k[o] < dp[i][cur] )
                                {
                                    dp[i][cur] = dp[i][cur - gap] + k[o];
                                }
                                cur += gap;
                            }
                        }
                    }    
                    int mn = -1;
                    int j;
                    for(j = 2000; j >= 0; j--)
                    {
                        if( -1 != dp[i][j] )
                        {
                            mn = dp[i][j];
                            break;
                        }
                    }
                    for( j = j - 1; j >= 0; j--)
                    {
                        if( -1 == dp[i][j] || mn < dp[i][j] )
                        {
                            dp[i][j] = mn;
                        }
                        else
                        {
                            mn = dp[i][j];
                        }
                    }
                }
            }
        }
        ll ans = 0;
        for(int i = 0; i < n ; i++)
        {
            int cur = dp[b[i]][a[i]];
            if( -1 == cur)
            {
                ans = -1;
                break;
            }
            else
            {
                ans += cur; 
            }
        }
        //printf("%I64d\n",ans);
        cout<<ans<<endl;
    }
}