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

const int MAXM = 1007;
const int MAXN = 100007;
const long long INF = 1e12;

int n, m;
int a[MAXN], b[MAXN], k[MAXM], p[MAXM]; 
long long f[12][MAXM];

int main() {
  while (scanf("%d%d", &n, &m) != -1) {
    
    // init
    for (int i = 0; i <= 10; i ++) {
      f[i][0] = 0;
      for (int j = 1; j <= MAXM; j ++) f[i][j] = INF;
    }

    for (int i = 0; i < n; i ++) scanf("%d%d", a+i, b+i);
    for (int i = 0; i < m; i ++) scanf("%d%d", k+i, p+i);

    for (int bi = 0; bi <= 10; bi ++) {
      for (int i = 0; i < m; i ++) {
        int atk = p[i] - bi;
        if (atk <= 0) continue;
        for (int j = 1; j <= MAXM; j ++) {
          f[bi][j] = min(f[bi][max(0, j - atk)] + k[i], f[bi][j]);
        }
      }
    }
    long long ans = 0;
    for (int i = 0; i < n; i ++) {
      if (f[b[i]][a[i]] >= INF) { ans = -1; break; }
      else ans += f[b[i]][a[i]];
    }
    printf("%lld\n", ans);
  }
  return 0;
}