#include <bits/stdc++.h>

#define N 100010
#define M 1010

using namespace std;

int a[N], b[N], k[M], p[M], f[11][M];

int main()
{
    int n, m;
    while(scanf("%d%d", &n, &m) != EOF)
    {
        for(int i = 1; i <= n; i++)
            scanf("%d%d", &a[i], &b[i]);
        for(int i = 1; i <= m; i++)
            scanf("%d%d", &k[i], &p[i]);
        for(int B = 0; B <= 10; B++)
        {
            memset(f[B], 0x3f, sizeof(f[B]));
            f[B][0] = 0;
            for(int i = 1; i <= m; i++)
            {
                int now = p[i] - B;
                if(now <= 0)continue;
                for(int j =    1; j <= 1000; j++)
                    f[B][j] = min(f[B][j], f[B][max(j - now, 0)] + k[i]);
            }
        }
        int flag = 1;
        long long ans = 0;
        for(int i = 1; i <= n; i++)
        {
            if(f[b[i]][a[i]] == 0x3f3f3f3f)
            {
                flag = 0;
                break;
            }
            ans += f[b[i]][a[i]];
        }
        if(!flag)puts("-1");
        else cout << ans << endl;
    }
}