# Print the polynomial (x + 1)^n
# Matt Bishop, February 27, 2012
# ECS 10, Winter Quarter 2012

# function to read and vet user selection
# returns: n, the exponent in (x + 1)^n
# NOTE: n must be non-negative; return -1 to quit
def getinput():
    # loop until we get good input
    while True:
        try:
            # get the input and check the type here
            n = int(input("n (EOF to quit): "))
        except EOFError:        # user wants to quit, so help her
            n = -1
            break
        except ValueError:      # user didn't enter a number
            print("You have to enter a non-negative n or EOF")
            continue
        # now check the value we read/were given
        if n >= 0:
            break
        # this is bad, so say so
        print("You have to enter a non-negative n or EOF")

    # it's non-negative to continue, -1 to quit
    return n

# function to compute n!
# parameter: n, must be non-negative integer
# returns: n! on success
#          -1 on failure (bad parameter)
def fact(n):
    # check for error in call
    if n < 0 or n != int(n):
        return -1

    # now compute n! by repeated multiplication
    fact = 1
    for i in range(1, n+1):
        fact *= i
    # return it
    return fact

# function to print cx^p intelligently
# parameter: c, the coefficient
#            p, the exponent
#            NOTE: assumes p >= 0
# side effect: prints cx^p as follows:
#            COEFFICIENT: if c == 1, prints "+"
#            if c == -1, prints "-"
#            if c > 0, prints "+ c"
#            if c < 0, prints "- c"
#            if c == 0, prints ""
#            POWER: if p == 0, prints c
#            if p == 1, prints x
#            otherwise prints x^p
def prcoeff(c, p):
    # as described in lead comment
    if c == 0:
        pass
    elif p == 0:
        # print coefficient only
        print("%d" % (c), end=' ')
    elif p == 1 and c > 0:
        # don't print exponent
        print("+ %dx" % (c), end=' ')
    elif p == 1 and c < 0:
        # don't print exponent
        print("- %dx" % (c), end=' ')
    elif c == -1:
        # don't print coefficient of 1
        print("- x^%d" % (p), end=' ')
    elif c < 0:
        # print it all neatly
        print("- %dx^%d" % (abs(c),p), end=' ')
    elif c == 1:
        # don't print coefficient of 1
        print("+ x^%d" % (p))
    else:
        # print it all neatly
        print("+ %dx^%d" % (c,p), end=' ')
        
def main():
    # get the input
    n = getinput()
    # if the input is negative, quit at once
    if n >= 0:
        # it's not -- for each term ...
        for i in range(n+1):
            # generate the binomial coefficient and print the polynomial
            prcoeff(fact(n) / (fact(i) * fact(n - i)), i)

main()