View Compilation Error

0_0_33780614_9029.cpp: In function 'int main()':
0_0_33780614_9029.cpp:10:21: error: 'n' was not declared in this scope
  for(int i = 2; i < n; i++)inv[i]=-mod/i*inv[mod%i]%mod+mod;
                     ^
0_0_33780614_9029.cpp:11:21: error: 'n' was not declared in this scope
  for(int i = 1; i < n; i++){
                     ^