/* N-ostos Fibonacci gia N<=45 
   f(i-1), f(i), f(i+1) fib arithmoi 
   0,1,1,2,3,5,8,13, ..... */
#include <iostream>
using namespace std;
 
int main(int argc, char *argv[])
{ int n, i, 
      fn_2=0, fn_1=1, fn=1;
  i=2; // Trexwn deikths arithmou Fib sthn akolouthia
  cout<<"Dose to deikth N<=45 tou arithmou \n";
  cout<<"pou anazhtame sthn akolou8ia Fib: ";
  cin>>n;
  while (i != n)
   { fn_2=fn_1;
     fn_1=fn;
     fn=fn_2+fn_1;
     i++;
   }
  cout << "O "<<n<<"-os Fibonacci einai o " <<fn<<endl;
  system("Pause");
  return 0;
}