l,n = [int(input()) for _ in range(2)]
w = list(map(int, input().split()))
cntDic = {}
sw = []
for i in range(1, l):
    cntDic[str(i)] = 0

for we in w:
    cntDic[str(we)] += 1

for i in range(1, l):
    for _ in range(cntDic[str(i)]):
        sw.append(i)

cnt = 0
for i, swe in enumerate(sw):
    cnt += swe
    if cnt > l:
        print(i)
        break