param

all_chars = 124
def maxcount(str, n): 
    count_chars = [0]*all_chars
    for i in range(n): 
        count_chars[ord(str[i])]+=1
    max_count = 0
    for i in range(all_chars):
        if (count_chars[i]>0):
            max_count+=1    
    return max_count 
  
def smallesteSubstring(str_input): 
    len_str = len(str_input)
    m=len(str_input)
    i=0
    j=0
    max_count = maxcount(str_input,len_str) 
    while i<len_str: 
        while j<len_str: 
            substr = str_input[i:j] 
            substr_len = len(substr) 
            sub_char_count = maxcount(substr,substr_len) 
            if max_count == sub_char_count and substr_len<m: 
                m=substr_len
            j+=1
        i+=1
    return m   

str_input=input()
length = smallesteSubstring(str_input)
print(length)