#include <iostream> using namespace std; int main() { int a=1; int b=1; int i; cin>>i; if(i=1||i=2){ cout<<1<<endl; } if(i<1||i>46){ cout<<"不存在"<<endl; } else{ for(i=3;i<=k;i++){ int sum=a+b; a=b; b=sum; } cout<<sum<<endl; } } return 0; }