#include #define FOR(i,a,b) for(int i = (a); i < (b); ++i) #define REP(i,n) FOR(i,0,n) #define SZ(n) (int)(n).size() #define ALL(n) (n).begin(), (n).end() #define MOD 1000003 #define INF 100000000 using namespace std; typedef long long LL; typedef vector VI; typedef pair PI; LL m[64] = {}; bool d(int i, int n) { if (i == n) { return m[i]; } else { m[i + 2] = m[i] + m[i + 1]; i++; return d(i, n); } } int main() { int n; cin >> n; m[0] = 1; m[1] = 1; d(0, n); cout << m[n] << endl; return 0; }