Ruby program to calculate the Greatest Common Divisor

num1=0
num2=0
rem=0
x=0
y=0

print "Enter number1: ";
num1 = gets.chomp.to_i;  

print "Enter number2: ";
num2 = gets.chomp.to_i;  

if (num1 > num2) 
    x = num1;
    y = num2;
else 
    x = num2;
    y = num1;
end

rem = x % y;

while (rem != 0) 
    x = y;
    y = rem;
    rem = x % y;
end

print "Greatest Common Divisor is: ",y;

Output:

Enter number1: 24
Enter number2: 21
Greatest Common Divisor is: 3