s=input()
a=[0]*26
for i in s:
    if "A"<=i<="Z":
        a[ord(i)-ord("A")]+=1
    elif "a"<=i<="z":
        n=ord(i)-ord("a")
        a[n]=a[n]+1
#找到出现次数最多的字母和未出现的字母
maxn=0;maxi=0;no=[]
for i in range(26):
    if a[i]==0:
        no.append(chr(ord("A")+i))
    elif a[i]>maxn:
        maxn=a[i]
        maxi=i

for i in range(26):
    if a[i]==maxn:
        print(chr(ord("A")+i),end=' ')
print()
print(maxn)
for i in no:
    print(i,end=' ')
#Saying and doing are two different things.