diff --git a/problem/CF6A/CF6A.cpp b/problem/CF6A/CF6A.cpp
new file mode 100644
index 00000000..1b6bd827
--- /dev/null
+++ b/problem/CF6A/CF6A.cpp
@@ -0,0 +1,21 @@
+// R38989380
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main() {
+    int a, b, c, d;
+    cin >> a >> b >> c >> d;
+    // abc abd acd bcd
+    if (a + b > c && a + c > b && b + c > a || a + b > d && a + d > b && b + d > a || a + c > d && a + d > c && c + d > a || b + c > d && b + d > c && c + d > b) {
+        cout << "TRIANGLE" << endl;
+    }
+    else if (a + b >= c && a + c >= b && b + c >= a || a + b >= d && a + d >= b && b + d >= a || a + c >= d && a + d >= c && c + d >= a || b + c >= d && b + d >= c && c + d >= b) {
+        cout << "SEGMENT" << endl;
+    }
+    else {
+        cout << "IMPOSSIBLE" << endl;
+    }
+    return 0;
+}