def truckTour(petrol_pumps):
    start_index = 0
    total_liters = 0
    total_distance = 0

    for i in range(len(petrol_pumps)):
        liters, distance = petrol_pumps[i]
        total_liters += liters
        total_distance += distance
        # Arriving to next petrol pump

        if total_liters - total_distance < 0:
            # Initialize start index before restarting in start index
            start_index = i + 1
            total_liters = 0
            total_distance = 0
    
    return start_index