View Compilation Error

0_0_20010929_2129.cpp: In function 'int main()':
0_0_20010929_2129.cpp:13:6: error: expected unqualified-id before numeric constant
  int 64 n;                 
      ^
0_0_20010929_2129.cpp:15:16: error: 'n' was not declared in this scope
 scanf("%I64d",&n);  
                ^