import sys
if __name__ == '__main__':
for x in sys.stdin:
a = x.strip().split(',')
# b = [1, 2, 3, 4, 6, 8, 9, 10]
b = list(map(int, a))
b.append(b[-1] + 2) # 確保邊界是自己想要的邊界
result = []
start = 0
end = 0
for i in range(len(b) - 1):
if b[i + 1] == b[i] + 1:
end += 1
else:
if start != end:
result.append("-".join([str(b[start]), str(b[end])]))
else:
result.append(b[start])
end = start = i + 1
print(result)
1,2,3,4,6,8,9,10
['1-4', 6, '8-10']