View Compilation Error

0_0_38929225_20994.cpp: In function 'int main()':
0_0_38929225_20994.cpp:19:44: error: expected ')' before '{' token
   19 |         while((~scanf ("%d",&n) && n != -1)
      |              ~                             ^
      |                                            )
   20 |         {
      |         ~