diff --git a/src/8/23/P2810.cpp b/src/8/23/P2810.cpp
new file mode 100644
index 0000000..826c512
--- /dev/null
+++ b/src/8/23/P2810.cpp
@@ -0,0 +1,73 @@
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+const int MAXN = 1000000;
+vector<vector<int>> tree;
+int a[MAXN + 5];
+
+// 合并两个有序数组到 res
+void mergeVectors(const vector<int>& A, const vector<int>& B, vector<int>& res) {
+    res.resize(A.size() + B.size());
+    int i = 0, j = 0, k = 0;
+    while (i < (int)A.size() && j < (int)B.size()) {
+        if (A[i] < B[j]) res[k++] = A[i++];
+        else res[k++] = B[j++];
+    }
+    while (i < (int)A.size()) res[k++] = A[i++];
+    while (j < (int)B.size()) res[k++] = B[j++];
+}
+
+void build(int node, int l, int r) {
+    if (l == r) {
+        tree[node].assign(1, a[l]);
+    } else {
+        int mid = (l + r) >> 1;
+        build(node << 1,     l,    mid);
+        build(node << 1 | 1, mid+1, r);
+        mergeVectors(tree[node<<1], tree[node<<1|1], tree[node]);
+    }
+}
+
+int query(int node, int l, int r, int L, int R, int C) {
+    if (r < L || R < l) {
+        return 0;
+    }
+    if (L <= l && r <= R) {
+        auto &v = tree[node];
+        int pos = int(std::lower_bound(v.begin(), v.end(), C) - v.begin());
+        return int(v.size()) - pos;
+    }
+    int mid = (l + r) >> 1;
+    return query(node<<1, l, mid, L, R, C)
+         + query(node<<1|1, mid+1, r, L, R, C);
+}
+
+int main(){
+    tree.resize(4 * MAXN + 5);
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+    int N, Q;
+    cin >> N >> Q;
+    for (int i = 0; i < N; i++) {
+        cin >> a[i];
+    }
+
+    build(1, 0, N-1);
+    while (Q--) {
+        char op;
+        cin >> op;
+        if (op == 'A') {
+            int L, R;
+            int C;
+            cin >> L >> R >> C;
+            L--; R--;
+            int ans = query(1, 0, N-1, L, R, C);
+            cout << ans << "\n";
+        } else {
+
+        }
+    }
+
+    return 0;
+}