def fib(n):
    sequence = []
    i = 0
    while i < n:
        if i == 0:
            sequence.append(1)
            i=i+1
        else:
            if i == 1:
                sequence.append(2)
                i=i+1
            else:
                sequence.append(sequence[i-1]+sequence[i-2])
                i=i+1
    return sequence[n-1]
 
 
def firstfib(n):
    m=1
    while fib(m) <= n:
        m=m+1
    return m
 
def evenfibsum(n):
    k = 0
    sum = 0
    while 2+3*k < firstfib(n):
        sum = sum + fib(2+3*k)
        k = k+1
    return sum
 
print evenfibsum(3)