diff --git a/2015_day_4/Makefile b/2015_day_4/Makefile
index 3b238af..bf0f9d9 100644
--- a/2015_day_4/Makefile
+++ b/2015_day_4/Makefile
@@ -1,5 +1,7 @@
 compile:
-	gcc day4.c -Werror=switch -o day4 -lcrypto
+	gcc day4.c -Werror=switch -o day4 -lcrypto -march=native -Ofast -flto
 
 run:
-	./day4
\ No newline at end of file
+	./day4
+run2:
+	./day4 2
\ No newline at end of file
diff --git a/2015_day_4/day4.c b/2015_day_4/day4.c
index 2a092c0..4370a7e 100644
--- a/2015_day_4/day4.c
+++ b/2015_day_4/day4.c
@@ -1,33 +1,104 @@
 #include <openssl/md5.h>
 #include <stdio.h>
 #include <string.h>
+#include <stdbool.h>
+#include <stdlib.h>
 
-int main(){
+int main(int argc, char* argv[]){
     printf("\nWEST");
     const char *input_string = "yzbqklnj";
     unsigned char output_digest[MD5_DIGEST_LENGTH];
     unsigned long long int iteration_number = 0;
-
+    unsigned long long int suffix = 0;
+    unsigned long long int count;
+    unsigned char output_digest_hex[MD5_DIGEST_LENGTH * 2 + 1];
+    bool initialisation = false;
     //creating empty md5 context
     MD5_CTX context;
 
-    zeroes = {0,0,0,0,0}
-    //comparing first 5 digits of output
-    while (memcmp(charx, zeros, 5) !=0){
-        if(!MD5_Init(&context)){
-            fprintf(stderr,"Error MD5init failed");
-            return 1;
-        }
-    //suffix generation
-    if(iteration_number !=0){
-        suffix = iteration_number +1;
-    }
-    suffix = 
-    
+    const char *zeroes = "000000";
+    if(argc == 1){
+        //comparing first 5 digits of output
+        while (strncmp(output_digest_hex, zeroes, 5) !=0){
+            printf("%s\n",output_digest_hex);
+            printf("loop %llu\n", iteration_number);
+            if(initialisation == false && iteration_number == 0){
+                MD5((const unsigned char*)input_string,strlen(input_string),output_digest);
+                iteration_number++;
+                for(int i = 0; i< MD5_DIGEST_LENGTH; i++){
+                    sprintf(&output_digest_hex[i * 2], "%02x", output_digest[i]);
+                }
+                output_digest_hex[32] = '\0';
+                initialisation = true;
+            }else if(iteration_number >= 1){
+                suffix = iteration_number;
+                count = snprintf(NULL, 0, "%llu", suffix);
+                char *suffix_string = malloc(count +1);
+                sprintf(suffix_string,"%llu",suffix);
+            
+                char *loop_input_string = calloc(1,8 + count + 1);
+                strcat(loop_input_string,input_string);
+                strcat(loop_input_string,suffix_string);
+
+                MD5((const unsigned char*)loop_input_string,strlen(loop_input_string),output_digest);
+                iteration_number++;
+                for(int i = 0; i< MD5_DIGEST_LENGTH; i++){
+                    sprintf(&output_digest_hex[i * 2], "%02x", output_digest[i]);
+                }
+                output_digest_hex[32] = '\0';
+                printf("\n%s\n",loop_input_string);
+                free(suffix_string);
+                free(loop_input_string);
+            } else {
+                //ERROR!
+                return 1;
+            }
+        
+
+        }} else {
+        while (strncmp(output_digest_hex, zeroes, 6) !=0){//Part 2 is to find the suffix which gives 6 leading zeroes on the output
+            printf("%s\n",output_digest_hex);
+            printf("loop %llu\n", iteration_number);
+            if(initialisation == false && iteration_number == 0){
+                MD5((const unsigned char*)input_string,strlen(input_string),output_digest);
+                iteration_number++;
+                for(int i = 0; i< MD5_DIGEST_LENGTH; i++){
+                    sprintf(&output_digest_hex[i * 2], "%02x", output_digest[i]);
+                }
+                output_digest_hex[32] = '\0';
+                initialisation = true;
+            }else if(iteration_number >= 1){
+                suffix = iteration_number;
+                count = snprintf(NULL, 0, "%llu", suffix);
+                char *suffix_string = malloc(count +1);
+                sprintf(suffix_string,"%llu",suffix);
+            
+                char *loop_input_string = calloc(1,8 + count + 1);
+                strcat(loop_input_string,input_string);
+                strcat(loop_input_string,suffix_string);
+
+                MD5((const unsigned char*)loop_input_string,strlen(loop_input_string),output_digest);
+                iteration_number++;
+                for(int i = 0; i< MD5_DIGEST_LENGTH; i++){
+                    sprintf(&output_digest_hex[i * 2], "%02x", output_digest[i]);
+                }
+                output_digest_hex[32] = '\0';
+                printf("\n%s\n",loop_input_string);
+                free(suffix_string);
+                free(loop_input_string);
+            } else {
+                //ERROR!
+                return 1;
+            }
+        
+
+        }            
+        }
+        printf("%s%llu\n", input_string,iteration_number -1);
+        printf("%s\n", output_digest_hex);
 
-    }
 
 }
 
 
-//input = yzbqklnj
\ No newline at end of file
+//input = yzbqklnj