#include <iostream>
 
using std::cout;
using std::cin;
using std::endl;
using std::cerr;
 
#include <stdexcept>
using std::out_of_range;
 
#include <limits>
 
class OUTofRage : public out_of_range
{
   public:
      OUTofRage()
          : out_of_range("Out Of Range\n") {}
} ;
 
long long fibonacci(long long target, long long numberOne, long long numberTwo);
 
int main() {
	try {
       cout << endl << fibonacci(91, 0, 1) << endl << endl;
	}
	catch( std::exception &ex ) {
		std::cout << "error:" << ex.what() << std::endl;
	}
    return 0;
}
 
long long fibonacci(long long target, long long numberOne, long long numberTwo)
{
    if(std::numeric_limits<decltype(numberOne)>::max() - numberOne < numberTwo) 
         throw OUTofRage();
 
    if(target == 0) 
        return numberOne + numberTwo;
 
    return fibonacci(target-1, numberTwo, numberOne + numberTwo);
}