local a:int = 0, b:int = 1, c:int = 1, n:int

n = int(input( "Enter n: "))
if n = 0 then
    print 0
    end
else if n = 1
    print 1
    end
end if

while n>2
    a = b
    b = c
    c = a + b
    n = n - 1
wend
print c