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

const LL inf = 10000000000000000;
int n, m;
LL a[100005], b[100005], p[1005];
LL k[1005], dp[2010][16];

void init()
{
    for(int i = 0; i <= 2005; ++i)
        for(int j = 0; j <= 15; ++j)
        {
            dp[i][j] = inf;
            if(i == 0) dp[i][j] = 0;
        }
    for(int i = 0; i < m; ++i)
    {
        for(int j = 0; j <= 10; ++j)
        {
            int damage = p[i] - j;
            if(damage < 0) continue;
            for(int v = damage; v <= 2005; ++v)
                dp[v][j] = min(dp[v][j], dp[v - damage][j] + k[i]);
        }
    }
    for(int i = 2000; i >= 0; --i)
        for(int j = 0; j <= 10; ++j)
            dp[i][j] = min(dp[i][j], dp[i + 1][j]);
}

int main()
{
    while(~scanf("%d %d", &n, &m))
    {
        for(int i = 0; i < n; ++i)
            scanf("%I64d %I64d", &a[i], &b[i]);
        for(int i = 0; i < m; ++i)
            scanf("%I64d %I64d", &k[i], &p[i]);
        init();
        LL ans = 0;
        int flag = 0;
        for(int i = 0; i < n; ++i)
        {
            if(dp[a[i]][b[i]] == inf)
            {
                flag = 1;
                break;
            }
            ans += dp[a[i]][b[i]];
        }
        if(flag) printf("-1\n");
        else printf("%I64d\n", ans);
    }
}