string problem =
@".3..7....
6..195...
.98....6.
8...6...3
4..8.3..1
7...2...6
.6....28.
...419..5
....8..79";
Sudoku sudoku = Sudoku.Parse(problem);
Sudoku solution = sudoku.Solutions().First();
Console.WriteLine(solution);
534678912
672195348
198342567
859761423
426853791
713924856
961537284
287419635
345286179