program SumOfFourDigitNumber;

var
number, sum, firstDigit, secondDigit, thirdDigit, fourthDigit: integer;

begin
write('Enter a four-digit number: ');
readln(number);

firstDigit := number div 1000;
secondDigit := (number mod 1000) div 100;
thirdDigit := (number mod 100) div 10;
fourthDigit := number mod 10;

sum := firstDigit + secondDigit + thirdDigit + fourthDigit;

writeln('The sum of the four-digit number is: ', sum);
end.