RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
  SYSCFG->EXTICR[4] &= (uint16_t)~SYSCFG_EXTICR4_EXTI15_PA;
  EXTI->IMR = EXTI_IMR_MR15;
  EXTI->RTSR = EXTI_RTSR_TR15;
  NVIC_EnableIRQ(EXTI4_15_IRQn);
  NVIC_SetPriority(EXTI4_15_IRQn,0);

  SYSCFG->EXTICR[1] &= (uint16_t)~SYSCFG_EXTICR1_EXTI0_PA;
  EXTI->IMR = EXTI_IMR_MR0;
  EXTI->RTSR = EXTI_RTSR_TR0;
  NVIC_EnableIRQ(EXTI0_1_IRQn);
  NVIC_SetPriority(EXTI0_1_IRQn,1);

 void EXTI4_15_IRQHandler(void)
{
  if ((EXTI->PR & EXTI_PR_PR15) != 0) 
  {
     EXTI->PR |= EXTI_PR_PR15;
     GPIOC->ODR ^= (1<<9);
  }
}

void EXTI0_IRQHandler(void)
{
  if ((EXTI->PR & EXTI_PR_PR0) != 0) 
      {
          EXTI->PR |= EXTI_PR_PR0;
         GPIOC->ODR ^= (1<<8);
       }
}