The task is to generate the correct answer for a given math problem.

Ex Input:
Problem: a and b together can complete work in 6 days . a alone starts working and leaves it after working for 4 days completing only half of the work . in how many days it can be completed if the remaining job is undertaken by b ?

Ex Output:
12


Ex Input:
Problem: tourist purchased a total of 30 travelers checks in $ 50 and $ 100 denominations . the total worth of the travelers checks is $ 1800 . how many checks of $ 50 denominations can he spend so that average amount ( arithmetic mean ) of the remaining travelers checks is $ 100 ?

Ex Output:
2


Ex Input:
Problem: the average of temperatures at noontime from monday to friday is 55 ; the lowest one is 45 , what is the possible maximum range of the temperatures ?

Ex Output:

40