def rescue_boats(people, limit):
    
    # Sort the list of people in ascending order of weight
    people.sort()
   
    # Initialize pointers for the lightest and heaviest person
    left = 0
    right = len(people) - 1

    # Initialize the number of boats needed
    boats = 0  

    # Loop through the list of people until all people have been rescued
    while left <= right:  
        
        # Check if the lightest and heaviest person can fit on the same boat
        if people[left] + people[right] <= limit:
            # If they can, move on to the next lightest person
            left += 1  
        
        # Move on to the next heaviest person
        right -= 1

        # Add a boat for the current group of people
        boats += 1 
    # Return the total number of boats needed
    return boats

# Driver code
def main():
    people = [[1, 2], [3, 2, 2, 1], [3, 5, 3, 4], [
        5, 5, 5, 5], [1, 2, 3, 4], [1, 2, 3], [3, 4, 5]]
    limit = [3, 3, 5, 5, 5, 3, 5]
    for i in range(len(people)):
        print(i + 1, "\tWeights = ", people[i], sep="")
        print("\tWeight Limit = ", limit[i], sep="")
        print("\tThe minimum number of boats required to save people are ",
              rescue_boats(people[i], limit[i]), sep="")
        print("-" * 100)


if __name__ == '__main__':
    main()