View Compilation Error

0_0_8622888_19894.cpp: In function `long long int C(int, int)':
0_0_8622888_19894.cpp:19: error: `_int64' undeclared (first use this function)
0_0_8622888_19894.cpp:19: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8622888_19894.cpp:19: error: expected `;' before "i"
0_0_8622888_19894.cpp:19: error: `i' undeclared (first use this function)