View Compilation Error

1013284_0_0_7191.cpp:3: error: `_int64' does not name a type
1013284_0_0_7191.cpp:5: error: `_int64' does not name a type
1013284_0_0_7191.cpp: In function `int main()':
1013284_0_0_7191.cpp:20: error: `sum' undeclared (first use this function)
1013284_0_0_7191.cpp:20: error: (Each undeclared identifier is reported only once for each function it appears in.)