#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>

using namespace std;

typedef long long ll;

const int maxn = 100000 + 5;
const int maxm = 1000 + 5;

int dp[maxm][12], a[maxn], b[maxn];

int main()
{
    int n, m;
    while(~scanf("%d%d", &n, &m))
    {
        memset(dp, 0x3f, sizeof(dp));
        for(int i = 0; i <= 10; ++i) dp[0][i] = 0;
        for(int i = 1; i <= n; ++i) scanf("%d%d", &a[i], &b[i]);
        for(int i = 1; i <= m; ++i)
        {
            int q, p;
            scanf("%d%d", &q, &p);
            for(int j = 1; j <= 1000; ++j)
            {
                for(int k = 0; k < p; ++k)
                {
                    dp[j][k] = min(dp[j][k], dp[max(0, j - (p - k))][k] + q);
                }
            }
        }
        ll ans = 0;
        for(int i = 1; i <= n; ++i)
        {
            if(dp[a[i]][b[i]] == 0x3f3f3f3f)
            {
                ans = -1;
                break;
            }
            ans += dp[a[i]][b[i]];
        }
        printf("%I64d\n", ans);
    }
    return 0;
}