1 #include 
      
        2 #include 
       
         3 #include 
        
          4 #include 
         
           5 using namespace std; 6  7 int f[30],n; 8  9 int main()10 {11     f[0]=0;12     f[1]=1;13     for(int i=2; i<21; i++)14     {15         f[i]=f[i-1]+f[i-2];16     }17     while(scanf("%d",&n)!=EOF)18     {19         if(n<=20)20         {21             printf("%d\n",f[n]);22             continue;23         }24         else25         {26             double m=-0.5*log(5.0)/log(10.0)+((double)n)*log((sqrt(5.0)+1.0)/2.0)/(log(10.0));27             m-=floor(m);28             m=pow(10.0,m);29             while(m<1000)30             {31                 m*=10;32             }33             printf("%d\n",(int)m);34         }35     }36     return 0;37 }