View Compilation Error

0_0_20010905_23914.cpp: In function 'int main()':
0_0_20010905_23914.cpp:13:2: error: 'int64' was not declared in this scope
  int64 n;                 
  ^
0_0_20010905_23914.cpp:15:16: error: 'n' was not declared in this scope
 scanf("%I64d",&n);  
                ^