View Compilation Error

0_0_6419127_31247.cpp:8: error: `_int64' does not name a type
0_0_6419127_31247.cpp: In function `bool find_num(long long int)':
0_0_6419127_31247.cpp:16: error: `Sum' undeclared (first use this function)
0_0_6419127_31247.cpp:16: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6419127_31247.cpp: In function `int main()':
0_0_6419127_31247.cpp:38: error: `Sum' undeclared (first use this function)