#include <cstdio>
#include <vector>
#include <algorithm>

const int MAXN = 1e5 + 10;

int n, m;
struct Seq {
  int l, r;
  int w;
};
std::vector<Seq> level[MAXN];
int levelchoose[MAXN];
long long ans;

bool CanChoose(Seq x, Seq y) {
  return x.l > y.r;
}

void dfs(int step, long long now) {
  if (step > m) {
    ans = std::max(ans, now);
    return ;
  }
  for (size_t i = 0; i < level[step].size(); ++i) {
    if (CanChoose(level[step][i], level[step - 1][levelchoose[step - 1]])) {
      levelchoose[step] = i;
      dfs(step + 1, now + level[step][i].w);
    }
  }
}

int main() {
  #ifdef LOCAL
    freopen("!input.in", "r", stdin);
    freopen("!output.out", "w", stdout);
  #else
    freopen("power.in", "r", stdin);
    freopen("power.out", "w", stdout);
  #endif

  level[0].push_back({0, 0, 0});
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; ++i) {
    int belong, w, l, r;
    scanf("%d %d %d %d", &belong, &w, &l, &r);
    level[belong].push_back({l, r, w});
  }

  dfs(1, 0);

  printf("%lld\n", ans);
  return 0;
}