diff --git a/problem/P1161/P1161.cpp b/problem/P1161/P1161.cpp
new file mode 100644
index 00000000..323331df
--- /dev/null
+++ b/problem/P1161/P1161.cpp
@@ -0,0 +1,21 @@
+// R36448353
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+int main() {
+    int n, t, ans;
+    n = t = ans = 0;
+    double a;
+    n = t = ans = 0;
+    cin >> n;
+    for(int i = 1 ; i <= n ; i++) {
+        cin >> a >> t;
+        for(int j = 1 ; j <= t ; j++) {
+            ans ^= int(j*a);
+        }
+    }
+    cout << ans << endl;
+    return 0;
+}
\ No newline at end of file