diff --git a/khj20006/202510/20 BOJ P5 AB.md b/khj20006/202510/20 BOJ P5 AB.md
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+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+int Q;
+multiset<string> a, b;
+
+int main() {
+    cin.tie(0)->sync_with_stdio(0);
+    
+    cin>>Q;
+    for(string o, s;Q--;) {
+        cin>>o>>s;
+        if(o == "find") {
+            ll ans = 0;
+            string tmp = "";
+            int acnt[1000]{};
+            for(int i=0;i<s.size()-1;i++) {
+                tmp += s[i];
+                acnt[i] = a.count(tmp);
+            }
+            tmp = "";
+            reverse(s.begin(), s.end());
+            for(int i=0;i<s.size()-1;i++) {
+                tmp += s[i];
+                ans += acnt[s.size()-2-i] * b.count(tmp);
+            }
+            cout<<ans<<'\n';
+        }
+        else {
+            bool rev = s == "B";
+            bool add = o == "add";
+            auto &c = rev ? b : a;
+            cin>>s;
+            if(rev) reverse(s.begin(), s.end());
+            
+            string tmp = "";
+            for(char j:s) {
+                tmp += j;
+                if(add) c.insert(tmp);
+                else c.erase(c.find(tmp));
+            }
+        }
+    }
+
+}
+```