3-1

mny = int(input("거스름돈을 입력해주세요. : "))
cnt = 0

for i in [500, 100, 50, 10]:
    cnt = cnt + (mny // i)
    mny = mny % i

print(cnt)

3-2

n, m, k = map(int, input().split())

arr = list(map(int, input().split()))

arr = sorted(arr, reverse=True)

if arr[0] == arr[1]:
    result = arr[0] * m
else:
    result = (arr[0] * k * (m // k)) + (arr[1] * (m % k))

print(result)

3-3

n, m = map(int, input().split())

card = []
minnum = []

for i in range(n):
    card = list(map(int, input().split()))
    minnum.append(min(card))
    card = []

print(max(minnum))

3-4

n, m = map(int, input().split())
cnt = 0

while n != 1:
    if n % m != 0:
        n = n - 1
        cnt += 1
    else:
        n =  n // m
        cnt += 1

print(cnt)