diff --git a/Commissions/flis/IMT/Case3/.envrc b/Commissions/flis/IMT/Case3/.envrc
new file mode 100644
index 0000000..17d6464
--- /dev/null
+++ b/Commissions/flis/IMT/Case3/.envrc
@@ -0,0 +1 @@
+use_nix
\ No newline at end of file
diff --git a/Commissions/flis/IMT/Case3/case3 b/Commissions/flis/IMT/Case3/case3
new file mode 100755
index 0000000..9d7d7a1
Binary files /dev/null and b/Commissions/flis/IMT/Case3/case3 differ
diff --git a/Commissions/flis/IMT/Case3/case3.c b/Commissions/flis/IMT/Case3/case3.c
new file mode 100644
index 0000000..bc5f736
--- /dev/null
+++ b/Commissions/flis/IMT/Case3/case3.c
@@ -0,0 +1,80 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+
+
+struct Node {
+    struct Node* children[10];
+    bool isEnd;
+};
+
+struct Node* newNode(void) {
+    struct Node *nNode = NULL;
+    nNode = (struct Node *) malloc(sizeof(struct Node));
+    if (nNode) {
+        nNode->isEnd = false;
+        for (int i = 0; i < 10; i++) {
+            nNode->children[i] = NULL;
+        }
+    }
+    return nNode;
+}
+
+int numbers[] = {113, 11354, 77777, 255044};
+
+int main(void) {
+    struct Node* root = newNode();
+    printf("%p\n", root);
+
+    int n_numbers = sizeof(numbers)/sizeof(int);
+    
+    for (int i = 0; i < n_numbers; i++) {       // Go through all the phone numbers in the global list
+        struct Node* pointer = root;            // Create a pointer that points to whatever part of the trie we're working on
+        char number[9];                         // A number has 8 + \0 chars
+        snprintf(number, 9, "%i", numbers[i]);  // Convert int to string
+        int len_number = strlen(number);
+        for (int j = 0; j < len_number - 1; j++) {  // loop over chars in the phone number
+            if (j == len_number - 1) {          // if we are at the last iteration
+                if (pointer->isEnd == true) {   // Check if we've seen the number before
+                    printf("Duplicate Number found at element %i, number %s", i, number);
+                    break;
+                }
+                else {                          // if we're at the last iteration, and isEnd isnt true, its either a new number OR we found a prefix
+                    bool continues = false;
+                    for (int k = 0; k < 10; k++) {
+                        if( pointer->children[k] != NULL) {
+                            continues = true;
+                        };
+                    };
+                    if (continues == true) {
+                        printf("FOUND PREFIX IN NUMBER\n");
+                        printf("%s and %s", number, number);
+                        while (pointer->isEnd != true) { // follow the first paths you can find
+                            for (int k = 0; k < 10; k++) {
+                                if( pointer->children[k] != NULL) {
+                                    pointer = pointer->children[k];
+                                    printf("%c", k + '0');
+                                    break;
+                                };
+                            };
+                        };
+                        printf("\n");
+                        return 0;
+                    };
+                };
+                pointer->isEnd = true;
+            }
+            else if (pointer->isEnd == true) {  // if we've already seen a shorter number with this prefix
+                printf("Found prefix!");
+                for (int k = 0; k < j; k++) {
+                    printf("%c", number[k]);
+                }
+                printf("\n");
+            };
+            int index = number[j+1] - '0';
+            pointer->children[index] = newNode();
+            pointer = pointer->children[index];
+        };
+    };
+}
\ No newline at end of file
diff --git a/Commissions/flis/IMT/Case3/shell.nix b/Commissions/flis/IMT/Case3/shell.nix
new file mode 100644
index 0000000..d364c29
--- /dev/null
+++ b/Commissions/flis/IMT/Case3/shell.nix
@@ -0,0 +1,5 @@
+with import <nixpkgs> {};
+stdenv.mkDerivation {
+  name = "c-shell";
+  buildInputs = [ gcc gnumake ];
+}