a=b=0
l=[]
n=gets.to_i
gets.chomp.chars{|x|a-=x<')'?1:-1;b<a&&b=a;l<<[a,b]}
a=b=0
l.sort_by{|c,d|[e=c<=>0,e>0?d:c-d]}.each{|c,d|b<a+d&&b=a+d;a+=c}
p n*(n+1)/2+a-2*b