View Compilation Error

0_0_21704770_5041.cpp:14:7: error: 'maxn' was not declared in this scope
 int a[maxn];  
       ^
0_0_21704770_5041.cpp: In function 'int main()':
0_0_21704770_5041.cpp:25:25: error: 'a' was not declared in this scope
             scanf("%d",&a[i]);  
                         ^