#include <iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<set>
using namespace std;
typedef long long ll;
const int N= 5+1e5;
const int inf = 0x3f3f3f3f;

int dp[1005][15], a[N], b[N], k[1005], p[1005];
//a : hp  b:fang   k: mp   p:  hurt
int main()
{
    int  n, m;
    while(~scanf("%d%d", &n, &m))
    {
        bool flag = 0;
        for(int i = 0; i <= 1000; i ++)
            for(int j = 0; j <= 10; j ++)
        {
            if(i)
                dp[i][j] = inf;
            else
                dp[i][j] = 0;
        }
        for(int i = 1; i <= n; i ++)
            scanf("%d%d", a+i, b+i);
        int o = a[6];
        for(int i = 1; i <= m; i ++)
            scanf("%d%d",k+i, p+i);
        for(int pos = 1; pos <= m; pos ++)
            for(int j = 0; j <= 10; j ++)
            {
                if(p[pos]<=j) break;
                for(int i = 1; i <= 1000; i ++)
                {
                    int  les = p[pos]-j;
                    if(i <= les) dp[i][j] = min(dp[i][j], k[pos]);
                    else
                        dp[i][j] = min(dp[i][j], dp[i-les][j] + k[pos]);
                }
            }
        ll ans = 0;
        int i = 1;
        for(; i <= n; i ++)
        {
            int x = a[i], y = b[i];
            if(dp[x][y]==inf)
            {
                puts("-1");
                goto l;
            }
            else
                ans = ans + dp[x][y];
        }
        cout<<ans<<endl;
        l : continue;
    }
    return 0;
}