View Compilation Error

0_0_28510215_24961.cpp:4:11: error: expected ',' or '...' before numeric constant
 #define n 20
           ^
0_0_28510215_24961.cpp:8:16: note: in expansion of macro 'n'
 void getSG(int n)
                ^
0_0_28510215_24961.cpp: In function 'int main()':
0_0_28510215_24961.cpp:4:11: error: expected unqualified-id before numeric constant
 #define n 20
           ^
0_0_28510215_24961.cpp:29:6: note: in expansion of macro 'n'
  int n,m,p;
      ^
0_0_28510215_24961.cpp:31:6: error: 'i' was not declared in this scope
  for(i=2;i<=16;i++)
      ^
0_0_28510215_24961.cpp:34:28: error: 'm' was not declared in this scope
  while(~scanf("%d %d %d",n,m,p))
                            ^
0_0_28510215_24961.cpp:34:30: error: 'p' was not declared in this scope
  while(~scanf("%d %d %d",n,m,p))
                              ^