#include <bits/stdc++.h>

using namespace std;
const int MAXN = 1e5+7;
const long long inf = 1e18;
typedef long long LL;
int n,m;
int a[MAXN],b[MAXN];
int p[1005],k[1005];
struct node
{
    int v,w;
} wupin[11][1005];
LL dp[11][2005];
LL ans[11][2005];


int main()
{
    while(~scanf("%d%d",&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]);
        //预处理物品
        for(int i = 0; i <= 10; ++i)
            for(int j = 0; j < m; ++j)wupin[i][j].w = -k[j],wupin[i][j].v = p[j] - i;
        //完全背包
        for(int i = 0; i <= 10; ++i)
        {
            for(int j = 0; j <= 2000; ++j)dp[i][j] = -inf;
            dp[i][0] = 0;
        }
        for(int i = 0; i <= 10; ++i)
            for(int j = 0; j < m; ++j)if(wupin[i][j].v>0)
                    for(int f = wupin[i][j].v; f <= 2000; ++f)
                    {
                        dp[i][f] = max(dp[i][f],dp[i][f-wupin[i][j].v] + wupin[i][j].w);
                    }
        for(int i = 0; i <= 10; ++i)
        {
            LL MAX = -inf;
            for(int j = 2000; j >= 0; --j)
            {
                if(dp[i][j] > MAX)MAX = dp[i][j];
                ans[i][j] = MAX;
            }
        }



        //处理怪物
        LL sum = 0;
        for(int i = 0; i < n; ++i)
        {
            if(ans[b[i]][a[i]] == -inf)
            {
                sum = -1;
                break;
            }
            else sum += -ans[b[i]][a[i]];
        }
        printf("%I64d\n",sum);
    }
    return 0;
}
/*
1 2
1000 5
100000 6
100000 1000
*/