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

using namespace std;
typedef long long ll;

const int maxn = 1005;
const ll INF = 0x3f3f3f3f3f3f3f3f;

ll dp[maxn*2][11],res;
int sum[maxn][11],k[maxn],p[maxn],n,m,x,y,ans;
bool flag;

void init(){
    memset(dp, 0x3f, sizeof(dp));
    memset(sum, 0, sizeof(sum));
    ans = 0, res = 0, flag = false;
    for (int j = 0; j <= 10; j++) dp[0][j] = 0;
    for (int i = 0; i < n; i++) {
        scanf("%d%d", &x, &y);
        sum[x][y]++;
    }
    for (int i = 0; i < m; i++) scanf("%d%d", &k[i], &p[i]);
}


int main() {
    while (~scanf("%d%d", &n, &m)) {
        init();
        for (int j = 0; j <= 10; j++) {
            for (int i = 0; i <= 1000; i++) {
                for (int h = 0; h < m; h++) {
                    if (p[h] <= j) continue;
                    if (dp[i][j] == INF) continue;
                    dp[i + p[h] - j][j] = min(dp[i + p[h] - j][j], dp[i][j] + k[h]);
                }
            }
            for (int i = 2000; i >= 0; i--) dp[i][j] = min(dp[i][j], dp[i + 1][j]);
        }
        for (int j = 0; j <= 10; j++) {
            for (int i = 0; i <= 1000; i++) {
                ans += sum[i][j];
                if (dp[i][j] < INF) {
                    res += ans * dp[i][j];
                    ans = 0;
                }
            }
            if (ans > 0) {puts("-1");flag = true;break;}
        }
        if (!flag) printf("%I64d\n", res);
    }
    return 0;
}