#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long LL;

const int N = 100010,M = 1010;
int a[N],b[N];
int k[M],p[M];
LL dp[M][15];

int main()
{
    int n,m;
    while(~scanf("%d%d", &n,&m))
    {
        int hp=0,mp=0,ak=0;
        for (int i = 1; i <= n; i ++ )
        {
            scanf("%d%d", &a[i],&b[i]);
            hp=max(a[i],hp);
            mp=max(b[i],mp);
        }
        for (int i = 1; i <= m; i ++ )
        {
            scanf("%d%d", &k[i], &p[i]);
            ak=max(ak,p[i]);
        }
        if(ak<=mp)//连护甲都打不穿
        {
            puts("-1");
            continue;
        }
        for (int i = 0; i <= 10; i ++ )
        {
            for (int j = 1; j <= hp; j ++ )
            {
                dp[j][i]=1e18;
                for (int u = 1; u <= m; u ++ )
                {
                    int damage=p[u]-i;
                    if(damage<=0)continue;//护甲都打不穿
                    if(damage>=j)//可以打死
                    {
                        dp[j][i]=min(dp[j][i],(long long)k[u]);
                    }
                    else
                    {
                        dp[j][i]=min(dp[j][i],dp[j-damage][i]+k[u]);
                    }
                }
            }
        }
        
        LL res=0;
        for (int i = 1; i <= n; i ++ )
        {
            res+=dp[a[i]][b[i]];//scanf("%d%d", &a[i],&b[i]);
        }
        printf("%lld\n",res);
    }
    return 0;
}