#include using namespace std; long long mod = 998244353; //入力が必ず-mod>= 1; } return ret; }; mint &operator=(const mint &b) = default; mint operator-() const {return mint(0)-(*this);} mint operator+(const mint b){return mint(v)+=b;} mint operator-(const mint b){return mint(v)-=b;} mint operator*(const mint b){return mint(v)*=b;} mint operator/(const mint b){return mint(v)/=b;} mint operator+=(const mint b){ v += b.v; if(v >= mod) v -= mod; return *this; } mint operator-=(const mint b){ v -= b.v; if(v < 0) v += mod; return *this; } mint operator*=(const mint b){v = v*b.v%mod; return *this;} mint operator/=(mint b){ if(b == 0) assert(false); int left = mod-2; while(left){if(left&1) *this *= b; b *= b; left >>= 1;} return *this; } mint operator++(int){*this += 1; return *this;} mint operator--(int){*this -= 1; return *this;} bool operator==(const mint b){return v == b.v;} bool operator!=(const mint b){return v != b.v;} bool operator>(const mint b){return v > b.v;} bool operator>=(const mint b){return v >= b.v;} bool operator<(const mint b){return v < b.v;} bool operator<=(const mint b){return v <= b.v;} mint pow(const long long x){return repeat2mint(v,x);} mint inv(){return mint(1)/v;} }; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); long long N,i; cin >> N; mint answer = 0,div2 = mint(1)/2; for(i=1; i*i<=N; i++){ mint maxv = N/i%mod; answer += maxv*(maxv-1)*div2*i; answer += maxv*(N%i+1); } while(i <= N){ mint next = ((N%i)/(N/i)+1)%mod; mint v = N/i%mod,m = N%i%mod; answer += div2*(((m+1+m+1-(next-1)*v))*next)*v; answer += div2*v*(v-1)*div2*((mint(2*i%mod)+(next-1))*next); i += (N%i)/(N/i)+1; } cout << answer.v << endl; }