N,M=list(map(int,input().split()))
s=[list(map(int,input().split())) for i in range(M)]

Num=0
A=[]
B=[]
C=[]
        
if N==3:
    if M==0:
        print(Num=100)
    
    else:
        for i in s:
            if i[0]==1:
                A.append(i[1])
            
            elif i[0]==2:
                B.append(i[1])
            
            elif i[0]==3:
                C.append(i[1])
    
        if len(A)==0:
            print(-1)
        elif min(A)==0:
            print(-1)
        else:
            Num+=min(A)*100
            if len(B)==0:
                pass
            elif len(B)!=0:
                Num+=min(B)*10
            if len(C)==0:
                pass
            elif len(C)!=0:
                Num+=min(C)
            print(Num)
        
elif N==2:
    if M==0:
        print(Num=10)
    
    else:    
        for i in s:
            if i[0]==1:
                B.append(i[1])
            
            elif i[0]==2:
                C.append(i[1])
        
        if len(B)==0:
            print(-1)
        elif min(B)==0:
            print(-1)
        else:
            Num+=min(B)*10
            if len(C)==0:
                pass
            elif len(C)!=0:
                Num+=min(C)
            print(Num)

elif N==1:
    if M==0:
        print(0)
    else;
        for i in s:
            if i[0]==1:
                C.append(i[1])
        
            if len(C)!=0:
                N+=min(C)
                print(Num)
            else:
                print(Num)
    
