Cleared / usr / bin / env on crash on MAC

I've accidentally deleted / usr / bin / env and this is causing problems when i want to run brew install python
I know it was very stupid, can anyone help it? I receive the following error:

brew install python3
/ usr / local / bin / brew: line 91: / usr / bin / env: no such file or directory
/ usr / local / bin / brew: line 91: exec: / usr / bin / env: can not execute: no file or directory of this type