/* Form the n-th Fibonacci number, n > 1. 12 March 2022 */
Fib: procedure (n) returns (fixed binary (31));
declare (i, n, f1, f2, f3) fixed binary (31);
f1 = 0; f2 = 1;
do i = 1 to n-2;
f3 = f1 + f2;
f1 = f2;
f2 = f3;
end;
return (f3);
end Fib;