#include #include using namespace atcoder; using namespace std; using ll=long long; using ld=long double; ld pie=3.141592653589793; ll mod=998244353; ll inf=1009999999999999990; vector>mul(vector>&a,vector>&b){ vector>c(a.size(),vector(b[0].size(),0)); for (ll i = 0; i < a.size(); i++) { for (ll j = 0; j < b[0].size(); j++) { for (ll k = 0; k < a[0].size(); k++) { c[i][j]+=(a[i][k]*b[k][j])%mod; c[i][j]%=mod; } } } return c; } vector>matpow(vector>a,ll n){ vector>b(a.size(),vector(a.size(),0)); for (ll i = 0; i < a.size(); i++) { b[i][i]=1; } while (n>0) { if (n%2) { b=mul(a,b); n-=1; }else{ a=mul(a,a); n/=2; } } return b; } int main(){ ll n; cin >> n; vector>a={{1,0,0},{0,1,1},{1,1,0}}; vector>b=matpow(a,n-1); cout << (b[1][0]+b[2][0])%mod << endl; }