#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; typedef unsigned int ui; const ll mod = 1000000007; typedef long double ld; const ll INF = mod * mod; typedef pair P; #define stop char nyaa;cin>>nyaa; #define rep(i,n) for(int i=0;i=0;i--) #define Rep(i,sta,n) for(int i=sta;i=1;i--) #define Rep1(i,sta,n) for(int i=sta;i<=n;i++) typedef complex Point; const ld eps = 1e-8; const ld pi = acos(-1.0); typedef pair LDP; typedef pair LP; ll dp[51]; int main() { int n; cin >> n; dp[0] = dp[1] = 1; Rep1(i, 2, 50) { dp[i] = dp[i - 1] + dp[i-2]; } cout << dp[n] << endl; //stop return 0; }