#define USER_PIN 7534
#include<stdio.h>

int main(void)
{
	int atm_pin,amount;
	while (1) {				/*Block 1 begins */
		printf("Enter PIN: ");
		scanf("%d", &atm_pin);
		if (atm_pin == 0)
			printf("PIN can't be zero.\n");
		else if (atm_pin > 9999)
			printf("PIN should not be more than 4 characters.\n");
		else if (atm_pin < 1000)
			printf("PIN should not be less than 4 characters.\n");
		else if (atm_pin != USER_PIN)
			printf("Incorrect PIN.\n");
		else {				/*Block 2 begins */

			printf("Enter amount to withdraw: ");
			scanf("%d",&amount);
			if (amount > 20000)
				printf("Can't withdraw more than Rs 20000.\n");
			else if (amount == 0)
				return 1;	
			else {			/*Block 3 begins */	
				printf("Processing transaction, take cash.\n");
				return 0;
			     }			/* Block 3 ends */
		
		    }				/* Block 2 ends */
		}				/* while loop ends */
		return 0;			/* Wil this statement ever be executed? */
	
}