Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N>=2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(moji)


Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=c
    else:
        if numbers[int(s)-1]==c:
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(3):
    if numbers[a]==' ':
        numbers[a]=0
if numbers[0]==0:
    del numbers[0]
    if numbers[0]==0:
        del numbers[0]
        if numbers[0]==0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(moji)


Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=map(int,input().split())
    if numbers[s-1]==' ':
        numbers[s-1]=c
    else:
        if numbers[s-1]==c:
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(3):
    if numbers[a]==' ':
        numbers[a]=0
if numbers[0]==0:
    del numbers[0]
    if numbers[0]==0:
        del numbers[0]
        if numbers[0]==0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))


Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=map(int,input().split())
    if numbers[s-1]==' ':
        numbers[s-1]=c
    else:
        if numbers[s-1]==c:
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(3):
    if numbers[a]==' ':
        numbers[a]=0
if numbers[0]==0:
    del numbers[0]
    if numbers[0]==0:
        del numbers[0]
        if numbers[0]==0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print(-1)
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))
       

Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=map(int,input().split())
    if numbers[s-1]==' ':
        numbers[s-1]=c
    else:
        if numbers[s-1]==c:
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(3):
    if numbers[a]==' ':
        numbers[a]=0
if numbers[0]==0:
    del numbers[0]
    if numbers[0]==0:
        del numbers[0]
        if numbers[0]==0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print(-1)
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(moji)
       

Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=map(int,input().split())
    if numbers[s-1]==' ':
        numbers[s-1]=c
    else:
        if numbers[s-1]==c:
            continue
        else:
            print('-1')
            kotae+=1
            break

for a in range(3):
    if numbers[a]==' ':
        numbers[a]=0
if numbers[0]==0:
    del numbers[0]
    if numbers[0]==0:
        del numbers[0]
        if numbers[0]==0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print(-1)
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(moji)
       

Fixed submission:
N,M=map(int,input().split())
numbers=[' ',]*N
kotae=0
for a in range(M):
    suuji=[]
    s,c=input().split()
    if numbers[int(s)-1]==' ':
        numbers[int(s)-1]=int(c)
    else:
        if numbers[int(s)-1]==int(c):
            continue
        else:
            print('-1')
            kotae+=1
            break
if numbers[0]==' ' and N==3:
    numbers[0]=1
if N==2 and numbers[0]==' ':
    numbers[0]=1
for a in range(N):
    if numbers[a]==' ':
        numbers[a]=0
if N==3:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
            if numbers[0] == 0:
                del numbers[0]
if N==2:
    if numbers[0] == 0:
        del numbers[0]
        if numbers[0] == 0:
            del numbers[0]
if kotae==0:
    if len(numbers)!=N:
        print('-1')
    else:
       moji=''
       for a in numbers:
           moji+=str(a)
       print(int(moji))