Is_correct = 1 ..

If String 1 1 = '[' &! String String._ 1 = ']' then Is_correct = 0
If String 1 1 = '{' &! String String._ 1 = '}' then Is_correct = 0
If String 1 1 = '(' &! String String._ 1 = ')' then Is_correct = 0
