codeforces 617A - Elephant

def sol(n):
    ans=0
    while n>0:
        if n>=5:
            n-=5
        elif n>=4:
            n-=4
        elif n>=3:
            n-=3
        elif n>=2:
            n-=2
        elif n>=1:
            n-=1
        ans+=1
    return ans
 
print(sol(int(input())))