Problem:
Coin Changing Problem

Find the minimum number of coins to make change for n cents using coins of denominations d1, d2,.., dm. The coins can be used any number of times.

Input

n m
d1 d2 ... dm

Two integers n and m are given in the first line. The available denominations are given in the second line.

Output

Print the minimum number of coins in a line.

Constraints

1 ≤ n ≤ 50000

1 ≤ m ≤ 20

1 ≤ denomination ≤ 10000

The denominations are all different and contain 1.

Sample Input 1

55 4
1 5 10 50

Sample Output 1

2

Sample Input 2

15 6
1 2 7 8 12 50

Sample Output 2

2

Sample Input 3

65 6
1 2 7 8 12 50

Sample Output 3

3

Solution in Python3 (judge verdict: Accepted)

n, m = map(int, input().strip().split())
d = [i for i in map(int, input().strip().split())]
assert len(d) == m

cands = sorted(d)
data = [i for i in range(n+1)]

for c in cands:
    for i in range(n+1):
        if i + c <= n and data[i+c] > data[i] + 1:
            data[i+c] = data[i] + 1
print(data[-1])