#include <iostream> using namespace std; const int maxn=21; long long f[maxn]={0}; int main() { int n; for(int i=1;i<=maxn;i++){ if(i==1) f[i]=1; else if(i==2) f[i]=2; else f[i]=f[i-1]+f[i-2]; } while(scanf("%d",&n)!=EOF){ printf("%lld\n",f[n...