View Compilation Error

0_0_21425920_26807.cpp:11:7: error: 'maxn' does not name a type
 const maxn = 10001
       ^
0_0_21425920_26807.cpp: In function 'void add(int, int)':
0_0_21425920_26807.cpp:21:16: error: 'maxn' was not declared in this scope
     while(pos<=maxn)
                ^
0_0_21425920_26807.cpp: In function 'int main()':
0_0_21425920_26807.cpp:39:24: error: 'n' was not declared in this scope
     while(~scanf("%d",&n))
                        ^