# nth Fibonacci with simple while loop - don't feed to stdin

print "Enter a positive integer: ";
define n = get;
print "The "; print n; print "th Fibonacci number is ";
define a = 1;
define b = 1;
while (2<n) (
  b = a+b;
  a = b-a;
  n = n-1;
);
print b;
print "\n";