$this_var = "#include "stm32f4xx.h"
uint16_t delay_count=0;
    void SysTick_Handler(void)
      {
        if (delay_count > 0)
            delay_count--;
      }
    void delay_c(uint16_t delay_temp)
        {
            delay_count=delay_temp;
            while (delay_count){}
        }
int main(void)
   {
    SysTick_Config(SystemCoreClock);

    RCC->AHB1ENR|=RCC_AHB1ENR_GPIOFEN;
    GPIOF->MODER = 0x00020000;
    GPIOF->OTYPER=0;
    GPIOF->OSPEEDR = 0;

    while(1)
    {
        GPIOF->ODR=0x0001;
        delay_c(3);
        GPIOF->ODR=0x0000;
        delay_c(3);
    }
}";