View Compilation Error

0_0_15580323_16079.cpp: In function 'int main()':
0_0_15580323_16079.cpp:5:2: error: '_int64' was not declared in this scope
  _int64 a;
  ^
0_0_15580323_16079.cpp:6:9: error: expected ';' before 'b'
  _int64 b;
         ^
0_0_15580323_16079.cpp:10:21: error: 'a' was not declared in this scope
   scanf("%lld%lld",&a,&b);
                     ^
0_0_15580323_16079.cpp:10:24: error: 'b' was not declared in this scope
   scanf("%lld%lld",&a,&b);
                        ^