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

#define MAXN 100010
#define MAXM 3010
#define INF 0x3F3F3F3F

using namespace std;

typedef long long i64;

int a[MAXN], b[MAXN], k[MAXM], p[MAXM], dp[12][MAXM];

void Calc(int n, int d, int* dp) {
  fill(dp, dp + MAXM, INF);
  dp[0] = 0;
  for (int i = 0; i < n; ++i) {
    if (p[i] <= d) continue;
    for (int j = p[i] - d; j < MAXM; ++j) {
      dp[j] = min(dp[j], dp[j - p[i] + d] + k[i]);
    }
  }
  for (int i = MAXM - 2; i; --i) {
    dp[i] = min(dp[i], dp[i + 1]);
  }
}

i64 Solve(int n, int m) {
  for (int i = 0; i <= 10; ++i) {
    Calc(m, i, dp[i]);
  }
  i64 ret = 0;
  for (int i = 0; i < n; ++i) {
    if (dp[b[i]][a[i]] >= INF) {
      return -1;
    }
    ret += (i64)dp[b[i]][a[i]];
  }
  return ret;
}

int main() {
  int n, m;
  while (~scanf("%d%d", &n, &m)) {
    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]);
    }
    i64 ans = Solve(n, m);
    cout << ans << endl;
  }
  return 0;
}