n=int(input())
s=input()
a=[x for x in s]
no="0123456789"
n1=[x for x in no]
b1="abcdefghijklmnopqrstuvwxyz"
b=[x for x in b1]
c1="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
c=[x for x in c1]
e1="!@#$%^&*()-+"
e=[x for x in e1]
d=0
for i in a:
	if i in n1:
		n1=[]
		d+=1
	if i in b:
		b=[]
		d+=1
	if i in c:
		c=[]
		d+=1
	if i in e:
		e=[]
		d+=1
print(4-d if 4-d>6-len(s) else 6-len(s))