16 lines
206 B
Python
16 lines
206 B
Python
from sys import stdin
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n=int(stdin.readline().rstrip())
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res=0
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while n>0:
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if n%5==0:
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res+=n//5
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break
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n-=3
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res+=1
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if n==1 or n==2:
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res=-1
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break
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print(res) |