A Graph Problem

Given an undirected graph of the following form with n nodes, 1 ≤ n ≤ 76: Your task is to calculate the number of subsets of nodes of the graph with the following properties: • no nodes in the subset should be connected • it shouldn’t be possible to add further nodes to the subset without violating the first condition For a graph with 5 nodes the number of subsets which fulfill the above conditions is 4. The subsets are {1,3,5},{2,4},{2,5},{1,4}. Input The input will consist of a sequence of numbers n, 1 ≤ n ≤ 76. Each number will be on a separate line. The input will be terminated by EOF. Output Output the number of subsets as described above on a single line. The number of all subsets will be less than 231. Sample Input 1 2 3 4 5 30 Sample Output 1 2 2 3 4 4410