Buggy python submission (verdict: Runtime Error):
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    for i in range(n):
        if p[i] == x:
            b = max(b,i-1)
            e = min(e,i+1)
            break
    #print(b,e)
    r = []
    s = []
    for i in range(p[b]-1,p[e]+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])

Fixed submission:
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    r = []
    s = []
    for i in range(min(p)-1,max(p)+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])

Buggy python submission (verdict: Runtime Error):
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    for i in range(n):
        if p[i] == x:
            b = max(b,i-1)
            e = min(e,i+1)
            break
    r = []
    s = []
    for i in range(p[b],p[e]+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])

Fixed submission:
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    r = []
    s = []
    for i in range(min(p)-1,max(p)+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])

Buggy python submission (verdict: Runtime Error):
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    for i in range(n):
        if p[i] == x:
            b = max(b,i-1)
            e = min(e,i+1)
            break
    #print(b,e)
    r = []
    s = []
    for i in range(p[b],p[e]+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])

Fixed submission:
import sys
import math
def I():return int(sys.stdin.readline().replace("\n",""))
def I2():return map(int,sys.stdin.readline().replace("\n","").split())
def S():return str(sys.stdin.readline().replace("\n",""))
def L():return list(sys.stdin.readline().replace("\n",""))
def Intl():return [int(k) for k in sys.stdin.readline().replace("\n","").split()]
def Lx(k):return list(map(lambda x:int(x)*-k,sys.stdin.readline().replace("\n","").split()))

x,n = I2()
if n != 0:
    p = Intl()
else:
    p = []
p.sort()
if not x in p:
    print(x)
else:
    b,e = 0,n-1
    r = []
    s = []
    for i in range(min(p)-1,max(p)+2):
        if i not in p:
            r.append(i)
            s.append(abs(x-i))
    print(r[s.index(min(s))])