#include<bits/stdc++.h>
using namespace std;

const int N = 100010 , M = 1010;
const long long inf = 1e16;

long long dp[11][M];
int a[N],b[N],k[M],p[M],q[M];

//void solve(int P,int n,int m )
//{
//    for (int i = 0; i < 2; ++i)
//        for (int j = 1; j <=m; ++j)
//            dp[P][i][j] = inf;
//    dp[P][0][0] = 0;
//
//    for (int i = 1; i <= n; ++i)
//        q[i] = p[i];
//    for (int i = 1; i <= n; ++i)
//        p[i] = max (p[i] - P , 0);
//
//    for (int i = 1; i <= n; ++i)
//    {
//        int i1 = i & 1 , i2 = i1 ^ 1;
//        for (int j = 1; j <= m; ++j)
//            dp[P][i1][j] = inf;
//
//        for (int j = 0; j <= m ; ++j)
//        {
//            //if (j - p[i] >= 0)
//            dp[P][i1][j] = min (dp[P][i1][j] , dp[P][i2][max(j-p[i],0)] + k[i]);
//        }
//
//        for (int j = m-1; j >= 0; --j)
//            dp[P][i1][j] = min (dp[P][i1][j] , dp[P][i1][j+1]);
//    }
//
//    for (int i = 1; i <=n; ++i)
//        p[i] = q[i];
//}


void solve(int P,int n,int m )
{
    for (int j = 1; j <=m; ++j)
        dp[P][j] = inf;
    dp[P][0] = 0;

    for (int i = 1; i <= n; ++i)
        q[i] = p[i];
    for (int i = 1; i <= n; ++i)
        p[i] = max (p[i] - P , 0);

    for (int i = 1; i <= n; ++i)
    {
        for (int j = 0; j <= m ; ++j)
        {
            //if (j - p[i] >= 0)
            dp[P][j] = min (dp[P][j] , dp[P][max(j - p[i],0)] + k[i]);
        }

        for (int j = m-1; j >= 0; --j)
            dp[P][j] = min (dp[P][j] , dp[P][j+1]);
    }

    for (int i = 1; i <=n; ++i)
        p[i] = q[i];
}

int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    //int tt,cas=0; scanf("%d",&tt);

    int n,m;
    while (scanf("%d%d",&n,&m) != EOF)
    {
        int MaxA = 0, MaxB = 0;
        long long ans = 0;

        for (int i = 1; i <= n; ++i)
        {
            scanf("%d%d",&a[i],&b[i]);
            MaxA = max( MaxA , a[i]);
            MaxB = max( MaxB , b[i]);
        }

        for (int i = 1; i <= m; ++i)
            scanf("%d%d",&k[i],&p[i]);

        for (int P = 0; P <= MaxB; ++P)
        {
            solve(P,m,MaxA);
        }


        for (int i = 1; i <= n; ++i)
        {
            ans += dp[b[i]][a[i]];
            ans = min( ans , inf );
        }

        if (ans == inf) ans = -1;
        printf("%I64d\n", ans );
    }

    return 0;
}