def gcd(a,b):
    """
    Args:
        a (int) - first number
        b (int) - second number
    
    Returns (int):
        The gcd of a and b
        
    Example:
        >>> a = 2025
        >>> b = 450
        >>> gcd(a,b)
        225
    """
    # make sure b > a
    if a > b:
        t = a
        a = b
        b = t    
    
    # if b is congruent to 0 mod a, then a is the gcd
    if (b % a) == 0:
        return a
    
    # if not, then take 1 step using euclids algorithm
    else:
        return gcd(a,b%a)