Explain the strategy to minimize total travel time for three people with one car to reach a city, where travel time is determined by the slowest person.
Given three positive integers a, b, and c representing the travel times of three people, return the minimum total time for all three to reach the city if only one car is available and each trip time equals the slowest passenger's time.
min_travel_time(a, b, c)
Three integers.
An integer, the minimum total travel time.
def min_travel_time(a, b, c):