View Compilation Error

0_0_20477960_19846.cpp: In function 'int main()':
0_0_20477960_19846.cpp:4:2: error: '_int64' was not declared in this scope
  _int64 a;
  ^
0_0_20477960_19846.cpp:5:20: error: 'a' was not declared in this scope
  while(scanf("%d",&a)!=EOF)
                    ^