input: Write a function to calculate the maximum possible revenue from the items with given weights and values using the knapsack algorithm. The function should take three parameters: the list of weights, the list of values, and the number of items. It should return the maximum revenue that can be achieved with a total capacity of 5.
  
  def knapsack(weights, values, n):
      W = 5
      K = [[0 for x in range(W+1)] for x in range(n+1)]
      for i in range(n+1):
          for w in range(W+1):
              if i==0 or w==0:
                  K[i][w] = 0
              elif weights[i-1] <= w:
                  K[i][w] = max(values[i-1] + K[i-1][w-weights[i-1]],  K[i-1][w])
              else:
                  K[i][w] = K[i-1][w]
      return K[n][W]
  
  assert knapsack([2, 1, 3], [4, 2, 3], 3) == 7
  assert knapsack([1, 2, 3], [6, 10, 12], 3) == 22
  assert knapsack([2, 3, 4], [3, 4, 5], 3) == 7
  assert knapsack([1, 1, 1], [10, 20, 30], 3) == 50
  assert knapsack([], [], 0) == 0
output: def knapsack(weights, values, n):
      W = 5
      K = [[0 for x in range(W+1)] for x in range(n+1)]
      for i in range(n+1):
          for w in range(W+1):
              if i==0 or w==0:
                  K[i][w] = 0
              elif weights[i-1] <= w:
                  K[i][w] = max(values[i-1] + K[i-1][w-weights[i-1]],  K[i-1][w])
              else:
                  K[i][w] = K[i-1][w]
      return K[n][W]