{==============================================================
	iterativeFib.p
	
	Started by Jeff Ondich on 10/23/96
	Last modified 10/23/96
	
	This program computes Fibonacci numbers iteratively.
 ==============================================================}

program fib(input,output);

var		N : integer;


{==============================================================
	Fibonacci returns the nth Fibonacci number.
 ==============================================================}
function Fibonacci( n : integer ) : integer;
var		new, current, previous : integer;
begin
	previous := 1;
	current := 1;

	while n > 2 do
	begin
		new := current + previous;
		previous := current;
		current := new;
		n := n - 1
	end;
		
	Fibonacci := current
end;


{==============================================================
	Main program
 ==============================================================}
begin
	write( 'N = ' );
	readln( N );
	
	writeln( 'The ', N, 'th fibonacci number is ', Fibonacci(N) )
end.