View Compilation Error

0_0_20886926_7749.cpp: In function 'int main()':
0_0_20886926_7749.cpp:3:2: error: 'int64' was not declared in this scope
  int64 sum;
  ^
0_0_20886926_7749.cpp:7:4: error: 'sum' was not declared in this scope
  { sum=0;
    ^