"""
Fibonacci 4
www.3d-meier.de
18.05.2019
"""

def Fibonacci(n):
    a = (1 + (5 ** 0.5)) ** n
    b = (1 - (5 ** 0.5)) ** n
    c = (2 ** n) * (5 ** 0.5)
    return int(round((a - b) / c))

def main():
    print(Fibonacci(7))

if __name__=='__main__':
    main()