diff --git a/P2859.cpp b/P2859.cpp
new file mode 100644
index 0000000..644329a
--- /dev/null
+++ b/P2859.cpp
@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+using namespace std;
+int n;
+struct node
+{
+    int l, r, index;
+    const bool operator<(const node &b) const
+    {
+        return r > b.r;
+    }
+} cow[50005];
+bool used[50005];
+int be[50005];
+
+int main()
+{
+    scanf("%d", &n);
+    int maxR = 0;
+    for (int i = 1; i <= n; i++)
+        scanf("%d%d", &cow[i].l, &cow[i].r), cow[i].index = i, maxR = max(maxR, cow[i].r);
+    sort(cow + 1, cow + n + 1, [](const node &a, const node &b)
+         { return a.l < b.l; });
+    int tot = 1, nx = 1;
+    priority_queue<node> q;
+    for (int t = 1; t <= maxR; t++)
+    {
+        while (!q.empty() && q.top().r < t)
+            used[be[q.top().index]] = 0,q.pop();
+        while (tot <= n && cow[tot].l <= t)
+        {
+            int stall = -1;
+            for (int j = 1; j < nx; j++)
+                if (!used[j])
+                {
+                    stall = j;
+                    break;
+                }
+            if (stall == -1)
+                stall = nx++;
+            used[stall] = 1;
+            be[cow[tot].index] = stall;
+            q.push(cow[tot]);
+            tot++;
+        }
+    }
+    printf("%d\n", nx - 1);
+    for (int i = 1; i <= n; i++)
+        printf("%d\n", be[i]);
+    return 0;
+}
\ No newline at end of file