View Compilation Error

0_0_35760961_16534.cpp: In function 'int main()':
0_0_35760961_16534.cpp:4:2: error: '_int64' was not declared in this scope
  _int64 n,sum1;
  ^
0_0_35760961_16534.cpp:7:13: error: 'n' was not declared in this scope
  while(cin>>n){
             ^
0_0_35760961_16534.cpp:8:3: error: 'sum1' was not declared in this scope
   sum1=0;
   ^