[STM32F746] UART Interrupt using CubeMX generated code

I want to get UART Interrupted data to vary LED blinking speed.

For example,If I send 1 then speed 100ms or send 2 then speed 200ms.

I made a cod using CubeMX and Interrupting with just pressing ''Enter'' works perfect(Not sending any data)

(I pressed ''Enter'' 3 times in Line Sender)

but If I send some character like below, It iterrupts just one time and never interrupt again with my further interrupt action.

Here is my Code.

First of al,l I am getting Terminal ''printf''output into Serial usingcode below in function ''HAL_UART_MspDeInit''in usart.c.

 /* USER CODE BEGIN 1 */ 
#ifdef __GNUC__ 
/* With GCC/RAISONANCE, small printf (option LD Linker->Libraries->Small printf set to 'Yes') calls __io_putchar() */ 
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch) 
#else 
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f) 
#endif /* __GNUC__ */ 
/**
 * @brief Retargets the C library printf function to the USART.
 * @param None
 * @retval None
 */ 
PUTCHAR_PROTOTYPE{ 
/* Place your implementation of fputc here */
 /* e.g. write a character to the EVAL_COM1 and Loop until the end of transmission */ HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF); 
return ch; } 
/* USER CODE END 1 */ 

in my main.c

while (1)
{
HAL_Dealy(100);
printf(''Hello!\r\n'');
}

in stm32f7xx_it.c

viod USART1_IRQHandler(void)

{

/* USER CODE BEGIN USART1_IRQn 0 */

if ((_HAL_UART_GET_FLAG(&huart1, UART_FLAG_RXNE) != RESET) && (__HAL_UART_GET_IT_SOURCE(&hurat1, UART_IT_RXNE) != RESET)

{

printf(''I will Interrupt You!!!\r\n'');

}

__HAL_UART_CLEAR_PEFLAG(&huart1);

/* USER CODE END USART1_IRQn 0 */

HAL_UART_IRQHandler(&huart1);

}

Do you have any idea what went wrong here?