script logic with multiple conditions

[#1]

Hello, 

I would like to create a script with dependants conditions such as : 

SI ( ACC1 < A ; REP_A ; SI (ACC1 < B ; REP_B; SI (ACC1< C; REP_C;0))), ACCOUNT = [ACCOUNT].[TARGET]

where the second condition is the value if False to the first condition.

Many thanks for help !