# Created by Donyo Ganchev, Agricultural University, town of Plovdiv, Bulgaria
# donyo@abv.bg
import math
import datetime
choice=None
def air():
f_y, f_m, f_d=input('Enter first date in format "year, month, day": ')
s_y, s_m, s_d=input('Enter second date in format "year, month, day": ')
f_pdi=float(input('Enter pdi observed at first date: '))
s_pdi=float(input('Enter pdi observed at second date: '))
f_date=datetime.date(f_y, f_m, f_d)
s_date=datetime.date(s_y, s_m, s_d)
sdif=str(s_date-f_date)
int_dif=int(sdif[0:2])
r=(1/float(int_dif))*math.log((s_pdi*(1-f_pdi))/(f_pdi*(1-s_pdi)))
print \
"""
"""
print "%2.10f" %r
while choice!="0":
print \
"""
Apparent Infection Rate Calculation
Created by Donyo Ganchev - Agricultural University, Plovdiv, Bulgaria
1 - Begin calculation
0 - Exit
"""
choice= raw_input("Choice: ")
if choice == "0":
exit()
elif choice=="1":
air()
