import sys
for line in sys.stdin.readlines():
line = line.strip()
ret = {}
m = len(line)
min_c = {}
for c in line:
ret[c] = line.count(c)
if ret[c] < m:
min_c = {c}
m = ret[c]
elif ret[c] == m:
min_c.add(c)
for c in min_c:
line = line.replace(c, '')
print(line)


京公网安备 11010502036488号