Maria and Steven were playing a ring toss game each ring can score either 5 points or 8 points

Maria said "I wonder what's the highest score that can't be made using any combination of five and eight"

Steven replied "I don't think it could be very high because I know you make every number from 40 and higher using different combinations of 5's and 8's"

what is the highest number that can't be formed using 5's and 8's?