Three powers Consider the set of all non-negative inte-

ger powers of 3. S = {1,3,9,27,81,...} Consider the sequence of all subsets of S ordered by the value of the sum of their elements. The question is simple: find the set at the n-th position in the sequence and print it in increasing order of its elements. Input Each line of input contains a number n, which is a positive integer with no more than 19 digits. The last line of input con- tains ‘0’ and it should not be processed. Output For each line of input, output a single line displaying the n-th set as described above, in the format used in the sample output. Sample Input 1 7 14 783 1125900981634049 0 Sample Output {} { 3, 9 } { 1, 9, 27 } { 3, 9, 27, 6561, 19683 } { 59049, 3486784401, 205891132094649, 717897987691852588770249 }