#include using i32 = std::int32_t; using i64 = std::int64_t; using u32 = std::uint32_t; using u64 = std::uint64_t; using usize = std::size_t; const i32 INF = 1001001001; const i64 LINF = 1001001001001001; const u32 MOD1 = 1000000007; const u32 MOD2 = 998244353; int main(){ std::ios::sync_with_stdio(false); std::cin.tie(nullptr); i64 n; std::cin>>n; i64 a=0,b=0,c=0; for(i32 i=1,j=0;i