1 write "Fib: ";

     2 read n;  

     3 minus1 := 0;

     4 minus2 := 1;

     5 while n > 0 do {

     6        temp := minus2;

     7        minus2 := minus1 + minus2;

     8        minus1 := temp;

     9        n := n - 1

    10 };

    11 write "Result: ";

    12 write minus2 

    13