Verified answer

noli [addressing one person] nolite [ to more than one person]

cogitare [ infinitive of the verb 'to think' - you use the infinitive after 'noli'or 'nolite']

modo OR solum = only [ avoid words like iustus which are connectefd to justice, not 'just' meaning 'only'!!]

currere = to run

sentne looks best like this: noli cogitare, currere solum - because that way you balance the two verbs for the two concepts against each other in the middle.