diff --git a/339D.cpp b/339D.cpp
new file mode 100644
index 0000000..a54bcb4
--- /dev/null
+++ b/339D.cpp
@@ -0,0 +1,42 @@
+#include<bits/stdc++.h>
+#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
+#define endl '\n'
+using namespace std;
+
+vector<int> segtree(530000,0);
+void update(int ind,int val,int s,int e,int ti,int op){
+    if(ind<s || e<ind)
+        return;
+    if(s==e){
+        segtree[ti] = val;
+        return;
+    }
+    int mid = (s+e)/2;
+    update(ind,val,s,mid,2*ti,1-op);
+    update(ind,val,mid+1,e,2*ti+1,1-op);
+    if(op)
+        segtree[ti] = segtree[2*ti] | segtree[2*ti+1];
+    else
+        segtree[ti] = segtree[2*ti] ^  segtree[2*ti+1];
+}
+
+
+int main(){
+    fast;
+    int bits,m;
+    cin>>bits>>m;
+    int n = 1<<bits;
+    int op = bits&1;
+    vector<int> a(n+1);
+    for(int i=1;i<=n;i++)
+        cin>>a[i];
+    for(int i=1;i<=n;i++){
+        update(i,a[i],1,n,1,op);
+    }
+    int ind,val;
+    for(int i=1;i<=m;++i){
+        cin>>ind>>val;
+        update(ind,val,1,n,1,op);
+        cout<<segtree[1]<<endl;
+    }
+}