[백준] 2839번 설탕 배달 (파이썬)

https://www.acmicpc.net/problem/2839

n = int(input())
arr = [3, 5]

INF = float('inf')
dp = [INF]*(n+1)
dp[0] = 0 

for i in range(3, n+1):
    for j in arr:
        if dp[i-j] != INF:
            dp[i] = min(dp[i], dp[i-j]+1)

if dp[n] != INF:
    print(dp[n])
else:
    print(-1)