function to match values in 3 columns

Hi Excel Experts,

I am trying to match a value from column 1 and check if it exist in col 2 and col 3.

If yes, then output the value(col 1) in the 4th column or just display "true"

Sample:
col1 col2 col3 col4
1 0 2 1 or true <- true because there is "1" in col 2 and col 3
2 0 1
3 1 0
4 3 5
5 5 6 5 or true


Thanks in advance for the help!!