#yuki_479

n,m=map(int,raw_input().split())
g=[]
for i in xrange(m):
 a,b=map(int,raw_input().split())
 g.append([a,b])
g.sort()
g.reverse()

l=[]
for i in xrange(m):
 if g[i][1] in l:
  continue
 l.append(g[i][0])
s=set(l)
res=0

for i in s:
 res+=1<<i
print bin(res)[2:]