#include <iostream>
#include <algorithm>

const int maxn = 1e5 + 7;
const int maxm = 1e3 + 7;
const long long inf = 1e16 + 7;
long long a[maxn], b[maxn], k[maxm], p[maxm], dp[11][2001];

int main() {
  long long n, m;
  while (std::cin >> n >> m) {
    for (int i = 0; i < n; ++i) {
      std::cin >> a[i] >> b[i];
    }
    for (int i = 0; i < m; ++i) {
      std::cin >> k[i] >> p[i];
    }
    for (int i = 0; i <= 10; ++i) {
      for (int j = 1; j <= 2000; ++j) {
        dp[i][j] = inf;
      }
      dp[i][0] = 0;
      for (int j = 0; j < m; ++j) {
        if (p[j] >= i) {
          for (int l = p[j] - i; l <= 2000; ++l) {
            dp[i][l] = std::min(dp[i][l], dp[i][l - p[j] + i] + k[j]);
          }
        }
      }
      for (int j = 1999; ~j; --j) {
        dp[i][j] = std::min(dp[i][j + 1], dp[i][j]);
      }
    }
    long long ans = 0;
    for (int i = 0; i < n; ++i) {
      ans += dp[b[i]][a[i]];
    }
    if (ans >= inf) {
      ans = -1;
    }
    std::cout << ans << std::endl;
  }
  return 0;
}