what is the value should be given over to the charge of account id in requistion import

guys I am gonna to import purchase requisition,what is the value should be given over to po_requisitions_interface_all.charge_account_id? in requistion import

I know it is General Ledger charge account; references to GL_CODE_COMBINATIONS;

but I donot know what is the exactly id i shoud give to the field, and it cannot be null in requistion import;

pls help,thx