a = open('input.txt').readline() 
 A = 'QWERTUIOPASDFGHJKLZCVBNM' 
 for i in A: 
     a = a.replace(i, '0') 
  
 b = [] 
 k = 0 
 for i in a: 
     if i == '0': 
         k += 1 
     else: 
         b.append(str(k)) 
         b.append(i) 
         k = 0 
 c = [] 
 for i in range(len(b) - 4): 
     p = b + ' ' + b[i + 1] + ' ' + b[i + 2] + ' ' + b[i + 3] + ' ' + b[i + 4] 
     c.append(p) 
  
 d = [] 
 for i in c: 
     if i.count('X') == 1 and i.count('Y') == 1: 
         d.append(i) 
  
 e = [] 
 for i in d: 
     k = 0 
     p = i.split() 
     for j in p: 
         if j.isdigit(): 
             k += int(j) 
         else: 
             k += 1 
     e.append(k) 
 print(max(e))