def elephant_steps(n):
if n < 5:
return 1
else:
i = 5
result = 0
r = 0
while i >= 1:
if n >= i:
r += n % i
result += n // i
n = r
r = 0
i -= 1
if r != 0:
result = result + r
return result
if __name__ == '__main__':
n = int(input())
print(elephant_steps(n))