def drawhistogram(hist):
    """ Draws a histogram of the given Dictionary's keys """
    for i in sorted(hist.keys()):
        print(i, end=': ')
        if i < 10:
            print(' ', end='')
        print('x'*hist[i])

def histogram(nums):
    """ Creates a Dictionary from a List of integers """
    d = dict()
    for num in nums:
        d[num] = d.get(num,0) + 1
    return d

def readints(filename):
    """ Reads all integers from a file into a List """
    nums = list()
    with open('nums.txt') as fh:

        for line in fh:
            parts = line.split()

            for part in parts:
                nums.append(int(part))

    return nums

# Read
nums = readints('nums.txt')

# Histogram
hist = histogram(nums)

# Draw
drawhistogram(hist)