View Compilation Error

0_0_13123346_12798.cpp:7:1: error: '_int64' does not name a type
 _int64 sum,num;
 ^
0_0_13123346_12798.cpp: In function 'int main()':
0_0_13123346_12798.cpp:35:3: error: 'sum' was not declared in this scope
   sum=0;
   ^
0_0_13123346_12798.cpp:41:4: error: 'num' was not declared in this scope
    num=d-i+1;
    ^