In the spherical shaped planet $X$ there are $2n$ gas stations. Every station is paired with one other station ,
and every two paired stations are diametrically opposite points on the planet.
Each station has a given amount of gas. It is known that : if a car with empty (large enough) tank starting 
from any station it is always to reach the paired station with the initial station (it can get extra gas during the journey).
Find all naturals $n$ such that for any placement of $2n$ stations for wich holds the above condotions, holds: 
there always a gas station wich the car can start with empty tank and go to all other  stations on the planet.(Consider that the car consumes a constant amount of gas per unit length.)
1. **Understanding the Problem:**
   - We have a spherical planet with $2n$ gas stations.
   - Each station is paired with another station located diametrically opposite.
   - A car can start from any station with an empty tank and reach its paired station.
   - We need to determine for which values of $n$ it is possible for a car to start from some gas station and visit all other stations on the planet.

2. **Analyzing the Conditions:**
   - Since each station is paired with a diametrically opposite station, the distance between any paired stations is the same.
   - The car can start from any station and reach its paired station, implying that the total gas available on the path from one station to its paired station is sufficient to cover the distance.

3. **Key Insight:**
   - For the car to visit all stations starting from one station, it must be able to complete a full circuit of the planet.
   - This means the total gas available at all stations must be sufficient to cover the total distance around the planet.

4. **Mathematical Formulation:**
   - Let the total distance around the planet be $D$.
   - The car must be able to travel a distance of $D$ starting from some station.
   - Since the car can start from any station and reach its paired station, the gas available at each station must be sufficient to cover half the distance around the planet, i.e., $D/2$.

5. **Summing Up the Gas:**
   - The total gas available at all $2n$ stations must be at least $D$ for the car to complete a full circuit.
   - Since the car can start from any station and reach its paired station, the gas at each station must be distributed in such a way that the total gas is sufficient for the car to travel the entire distance $D$.

6. **Conclusion:**
   - For the car to be able to start from some gas station and visit all other stations, the total gas available at all stations must be sufficient to cover the total distance around the planet.
   - This condition is independent of the value of $n$ as long as the total gas is sufficient.

The final answer is $\boxed{n \text{ can be any natural number}}$