#include <iostream>
using namespace std;
int main()
{
int input;
int patterns[50]={0,1,2};
int static soFarMaxLength = 2;
int ans;
while(cin>>input){
if(input==0){
break;
}
else if(input<=soFarMaxLength){
ans = patterns[input];
}
else{
for(int i=soFarMaxLength+1; i<=input ; i++){
patterns[i] = patterns[i-2] + patterns[i-1];
}
ans = patterns[input];
soFarMaxLength = input;
}
cout<<ans<<endl;
}
return 0;
}