diff --git a/problem/P1143/P1143.cpp b/problem/P1143/P1143.cpp
new file mode 100644
index 00000000..56f7ec66
--- /dev/null
+++ b/problem/P1143/P1143.cpp
@@ -0,0 +1,77 @@
+// R38915106
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int ctoi(char c) {
+    int r;
+    switch (c) {
+        case 'A':
+            r = 10;
+            break;
+        case 'B':
+            r = 11;
+            break;
+        case 'C':
+            r = 12;
+            break;
+        case 'D':
+            r = 13;
+            break;
+        case 'E':
+            r = 14;
+            break;
+        case 'F':
+            r = 15;
+            break;
+        default:
+            r = c - '0';
+            break;
+    }
+    return r;
+}
+
+char itoc(int x) {
+    char r;
+    switch (x) {
+        case 10:
+            r = 'A';
+            break;
+        case 11:
+            r = 'B';
+            break;
+        case 12:
+            r = 'C';
+            break;
+        case 13:
+            r = 'D';
+            break;
+        case 14:
+            r = 'E';
+            break;
+        case 15:
+            r = 'F';
+            break;
+        default:
+            r = x + '0';
+            break;
+    }
+    return r;
+}
+
+int main() {
+    long long i, n = 0, p1, p2, x = 1;
+    string    s, res = "";
+    cin >> p1 >> s >> p2;
+    for (i = s.size() - 1; i >= 0; i--) {
+        n += ctoi(s[i]) * x;
+        x *= p1;
+    }
+    while (n != 0) {
+        res = itoc(n % p2) + res;
+        n /= p2;
+    }
+    cout << res << endl;
+    return 0;
+}