diff --git a/6/A/triangle.cc b/6/A/triangle.cc
new file mode 100644
index 0000000..d141824
--- /dev/null
+++ b/6/A/triangle.cc
@@ -0,0 +1,53 @@
+/*
+* STATUS = ACCEPTED
+*/
+
+#include <cstdio>
+#include <algorithm>
+#include <stack>
+#include <cstring>
+#include <set>
+#include <iostream>
+
+using namespace std;
+
+#define FOR(i,n)   for(int i=0; i<n; ++i)
+#define FORI(i,a,n)   for(int i=a; i<n; ++i)
+#define SZ(c)      ((int)c.size())
+
+int main()
+{
+    #ifndef ONLINE_JUDGE
+        freopen("triangle.in","r",stdin);
+    #endif
+
+    int sides[4];
+    bool triangle = false, segment = false;
+
+    FOR(i,4) scanf("%d", &sides[i]);
+
+    FOR(i,4)
+    {
+        FORI(j, i+1, 4)
+        {
+            int low_bound = abs(sides[i] - sides[j]);
+            int upper_bound = sides[i] + sides[j];
+            FORI(k, j+1, 4)
+            {
+                if(sides[k] == low_bound || sides[k] == upper_bound)
+                    segment |= true;
+                else if(sides[k] > low_bound && sides[k] < upper_bound)
+                    triangle |= true;
+            }
+        }
+    }
+
+    if(triangle)
+        printf("TRIANGLE\n");
+    else if(segment)
+        printf("SEGMENT\n");
+    else
+        printf("IMPOSSIBLE\n");
+
+    return 0;
+}