백준 2839 파이썬

1.문제

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

2.코드

n=int(input())
b=str(n)
a=b[-1]
if n>=3:
    if a in ['2','4','7']:
        if n%3 != 0:
            print(-1)
        else :
            print(int(n/3))
    elif a in ['0','5']:
        print(int(n/5))
    elif a in ['3','6','9']:
        print((n//10)*2+int(int(a)/3))
    elif a=='1' :
        print(int(n/5)+1)
    else :
        print(n//5+1)
else:print(-1)

n=int(input())
a=0
while (n>=0):
    if n%5 == 0:
        a+= n//5
        print(a)
        break
    n-=3
    a+=1
else : print(-1)

3.코드해설