k = []
word = ""
M= 0
while True:
try:
a=input()
except:
break
k.extend(a.split())
for i in k:
c = 0
s = 0
e = 0
for j in i:
if (ord('a') <= ord(j) <= ord('z') or ord('A') <= ord(j) <= ord('Z') or j == '-'):
c+=1
e+=1
if c>M:
M=c
word=i[s:e]
else:
e+=1
s=e
c=0
print(word.lower())