import sys
sys.path.append("lib")
from num_fns import isDivBy

def fib(i):
    if i == 1:
        return 1
    elif i == 2:
        return 2
    return fib(i - 1) + fib(i - 2)

sum = 0

for i in range(1, 1000000):
    curr = fib(i)
    if curr > 4000000:
        break
    if isDivBy(curr, 2): sum += curr

print(sum)