void task_1(char *iban, char expr[MAX_TEXTLEN])
{
	/* REPLACE FOLLOWING LINE WITH YOUR SOLUTION */
	//   task_1_DEMO(iban, expr);


	char chars[4]={iban[0],iban[1],iban[2],iban[3]};

	int counter=0;
	for (int i = 0; iban[i] !='\0'; ++i)
	{
		if(iban[i+4]!= '\0'){
			iban[i]=iban[i+4];
		}else {
			counter=i;
			break;
		}
	}
	for(int i =0; i < 4; ++i){
		iban[counter]=chars[i];
		counter++;

	}

	counter = 0;
	for (int i = 0; iban[i] != '\0'; ++i)
	{
		if (isdigit(iban[i]) ==0)
		{
			int number = (int) iban[i] - 55;
			expr[counter]= (number /10) + '0';
			expr[counter+1]= (number%10) + '0';
			counter+=2;
		}
		else{
			expr[counter]=iban[i];
			counter++;
		}
	}

	expr[counter+1]=' ';
	expr[counter+2]= '%';
	expr[counter+3]= ' ';
	expr[counter+4]= '9';
	expr[counter+5]='7';
	expr[counter+6]='\0';
}