diff --git a/main.c b/main.c
index 97869be..1a3abfe 100644
--- a/main.c
+++ b/main.c
@@ -2,20 +2,20 @@
 #include <stdbool.h>
 #include "tm4c123gh6pm.h"
 // SysTick memory-mapped registers
-#define STCTRL *((volatile uint32_t *) 0xE000E010)          // CONTROL AND STATUS
-#define STRELOAD *((volatile uint32_t *) 0xE000E014)        // RELOAD VALUE
-#define STCURRENT *((volatile uint32_t *) 0xE000E018)       // CURRENT VALUE
-#define CLOCK_HZ 16000000       // CLOCK FREQUENCY OF EK-TM4C123GXL
+#define STCTRL *((volatile uint32_t *) 0xE000E010)                  // CONTROL AND STATUS
+#define STRELOAD *((volatile uint32_t *) 0xE000E014)                // RELOAD VALUE
+#define STCURRENT *((volatile uint32_t *) 0xE000E018)               // CURRENT VALUE
+#define CLOCK_HZ 16000000                                           // CLOCK FREQUENCY OF EK-TM4C123GXL
 #define SYSTICK_RELOAD_VALUE(us) ((CLOCK_HZ / 1000000) * (us) - 1)  // SYSTICK RELOAD VALUE
 
 void GPIO_PORT_F_init(void)
 {
-    SYSCTL_RCGC2_R |= 0x00000020;             // ENABLE CLOCK TO GPIOF
-    GPIO_PORTF_LOCK_R = 0x4C4F434B;           // UNLOCK COMMIT REGISTER
-    GPIO_PORTF_CR_R   = 0x1F;                 // MAKE PORTF0 CONFIGURABLE
-    GPIO_PORTF_DEN_R  = 0x1F;                 // SET PORTF DIGITAL ENABLE
-    GPIO_PORTF_DIR_R  = 0x0E;                 // SET PF0, PF4 as input and PF1, PF2 and PF3 as output
-    GPIO_PORTF_PUR_R  = 0x11;                 // PORTF PF0 and PF4 IS PULLED UP
+    SYSCTL_RCGC2_R |= 0x00000020;            // ENABLE CLOCK TO GPIOF
+    GPIO_PORTF_LOCK_R = 0x4C4F434B;          // UNLOCK COMMIT REGISTER
+    GPIO_PORTF_CR_R   = 0x1F;                // MAKE PORTF0 CONFIGURABLE
+    GPIO_PORTF_DEN_R  = 0x1F;                // SET PORTF DIGITAL ENABLE
+    GPIO_PORTF_DIR_R  = 0x0E;                // SET PF0, PF4 as input and PF1, PF2 and PF3 as output
+    GPIO_PORTF_PUR_R  = 0x11;                // PORTF PF0 and PF4 IS PULLED UP
 
     NVIC_EN0_R |= 1 << 30;
     GPIO_PORTF_IS_R  = 0x00;                 // Make it edge-sensitive
@@ -54,3 +54,12 @@ void GPIOF_interruptHandler(void)            // Interrupt handler for GPIO Port
         GPIO_PORTF_ICR_R = 0x01;             // CLEAR INTERRUPT FLAG FOR SWITCH 1
     }
 }
+
+int main(void)                               // MAIN FUNCTION
+{
+    GPIO_PORT_F_init();                      // GPIO INITIALISATION FUNCTION
+    systick_setting();                       // SYSTICK SETUP
+    while (1)
+    {                                        // DO NOTHING
+    }
+}