View Compilation Error

2_16309_1140369_14668.cpp: In function `void solve()':
2_16309_1140369_14668.cpp:18: error: `_int64' undeclared (first use this function)
2_16309_1140369_14668.cpp:18: error: (Each undeclared identifier is reported only once for each function it appears in.)
2_16309_1140369_14668.cpp:18: error: expected `;' before "ans"
2_16309_1140369_14668.cpp:25: error: `ans' undeclared (first use this function)