#include <bits/stdc++.h> using namespace std; int main() { int n,i,sum=1; cin>>n; int a[40]={0,1,1,2,3,5,8}; for (i=2;i<=n;i++)//控制行数n { a[i]=a[i-1]+a[i-2]; } cout<<a[n-1]; return 0; }