Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
sc = [list(map(int, input().split())) for _ in range(M)]
a=str(0)*N
A=[a[i] for i in range(len(a))]
x=0
#print(sc)
b=[]
c=[]
for i in range(M):
    if (sc[i][0] == 1) and (sc[i][1]==0) and (N!=1):
        a=-1
        break
    else:
        if (sc[i][0]) in b:#左から何桁目の情報が既にある場合、既に登録されているその桁の値と新たに登録しようとしてるその桁の値が異なるとき弾く
            if sc[i][1]!=int(c[b.index(sc[i][0])]):
                print(c[b.index(sc[i][0])])
                x=-1
                break
        else:
            A[sc[i][0]-1]=str(sc[i][1])
            b.append(sc[i][0])
            c.append(sc[i][1])
        
if b==[] and (N!=1):
    a=-1
    print(a)
elif (1 not in b) and(N!=1):
    A[0]=str(1)
    a="".join(A)
    print(a)
elif  (1 not in b) and (2 not in b):
    A[0]=str(1)
    A[1]=str(0)
    a="".join(A)
    print(a)
elif x==-1:
    print(-1)
else:
    a="".join(A)
    print(a)

Fixed submission:
N,M=map(int,input().split())
sc = [list(map(int, input().split())) for _ in range(M)]
a=str(0)*N
A=[a[i] for i in range(len(a))]
x=0
#print(sc)
b=[]
c=[]
for i in range(M):
    if (sc[i][0] == 1) and (sc[i][1]==0) and (N!=1):
        x=-1
        break
    else:
        if (sc[i][0]) in b:#左から何桁目の情報が既にある場合、既に登録されているその桁の値と新たに登録しようとしてるその桁の値が異なるとき弾く
            if sc[i][1]!=int(c[b.index(sc[i][0])]):
                #print(c[b.index(sc[i][0])])
                x=-1
                break
        else:
            A[sc[i][0]-1]=str(sc[i][1])
            b.append(sc[i][0])
            c.append(sc[i][1])
if x==-1:
    print(-1)      
elif b==[] and (N!=1):
    if N==2:
        print(10)
    elif N==3:
        print(100)
elif (1 not in b) and(N!=1):
    A[0]=str(1)
    a="".join(A)
    print(a)
elif  (1 not in b) and (2 not in b) and (N==3):
    A[0]=str(1)
    A[1]=str(0)
    a="".join(A)
    print(a)

else:
    a="".join(A)
    print(a)

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
sc = [list(map(int, input().split())) for _ in range(M)]
a=str(0)*N
A=[a[i] for i in range(len(a))]

#print(sc)
b=[]
c=[]
for i in range(M):
    if N==1:
        if (sc[i][0] == 1) and (sc[i][1]==0):
            a=-1
            break
        elif (sc[i][0]) in b:
            if sc[i][1]<int(A):
                A=str(sc[i][1])
        else:
            A[sc[i][0]-1]=str(sc[i][1])
            b.append(sc[i][0])
        c.append(sc[i][1])
    elif (sc[i][0] == 1) and (sc[i][1]==0):
        a=-1
        break
    else:
        if (sc[i][0]) in b:
            if sc[i][1]<int(A[sc[i][0]-1]):
                A[sc[i][0]-1]=str(sc[i][1])
        else:
            A[sc[i][0]-1]=str(sc[i][1])
            b.append(sc[i][0])
        c.append(sc[i][1])
        
if b==[]:
    a=-1
    print(a)
elif (1 not in b):
    a=-1
    print(a)
else:
    a="".join(A)
    print(a)

Fixed submission:
N,M=map(int,input().split())
sc = [list(map(int, input().split())) for _ in range(M)]
a=str(0)*N
A=[a[i] for i in range(len(a))]
x=0
#print(sc)
b=[]
c=[]
for i in range(M):
    if (sc[i][0] == 1) and (sc[i][1]==0) and (N!=1):
        x=-1
        break
    else:
        if (sc[i][0]) in b:#左から何桁目の情報が既にある場合、既に登録されているその桁の値と新たに登録しようとしてるその桁の値が異なるとき弾く
            if sc[i][1]!=int(c[b.index(sc[i][0])]):
                #print(c[b.index(sc[i][0])])
                x=-1
                break
        else:
            A[sc[i][0]-1]=str(sc[i][1])
            b.append(sc[i][0])
            c.append(sc[i][1])
if x==-1:
    print(-1)      
elif b==[] and (N!=1):
    if N==2:
        print(10)
    elif N==3:
        print(100)
elif (1 not in b) and(N!=1):
    A[0]=str(1)
    a="".join(A)
    print(a)
elif  (1 not in b) and (2 not in b) and (N==3):
    A[0]=str(1)
    A[1]=str(0)
    a="".join(A)
    print(a)

else:
    a="".join(A)
    print(a)