You have to catch the snorlax thats blocking the way to pallet town.
To make snorlax move you much have fixed the magnet train. Go to the power plant and fix the magnet train then you go to lavender town. Go inside the radio station and talk to everyone. This guy gives you a upgrade for your poke-gear. Then go to snorlax and go to your poke-gear radio.
At the way top there is poke-flute.
Then talk to snorlax and he/her will fight you. Take lv 50+ pokemon with you.
After you catch snorlax he/her will be holding leftover you were looking for.
To make snorlax move you much have fixed the magnet train. Go to the power plant and fix the magnet train then you go to lavender town. Go inside the radio station and talk to everyone. This guy gives you a upgrade for your poke-gear. Then go to snorlax and go to your poke-gear radio.
At the way top there is poke-flute.
Then talk to snorlax and he/her will fight you. Take lv 50+ pokemon with you.
After you catch snorlax he/her will be holding leftover you were looking for.