A great Russian scientist Ivan Ivanowich Ivanow made experiments with a flea.

He said: Jump, flea! and it jumped 40 centimetres high.

So he took a pencil (a big Russian invention) and put the following record in the experimental log: I said: Jump,flea! and it jumped 40 cm.

Then he tore off one of the fleas legs. He said: Jump, flea! and it jumped 30 centimetres high. He recorded: When I tore off one leg, the flea jumped 30 cm.

Then he continued tearing off other legs and the flea jumped 20, 10, and 2 centimeters high, respectively. Everything was recorded in the log book.

When only 1 leg remained, the poor flea jumped only 1 millimeter and a half high. Again, it was recorded.

Finally he tore off the last leg. He said: Jump, flea!. No response.

He said again (in a high voice): Jump, flea!. Nothing.

He shouted: Jump, flea!!!. The flea did not move.

So Ivan Ivanowich Ivanow took a pencil for the last time and wrote: I tore off all fleas legs and it cannot hear.