N=int(input())
E=list(map(int,input().split()))
if len(E)==3:
    print("\"assert\"")
else:
    F=int(input())
    G=int(input())
    H=E[0]
    ushitapunichiakun=[]
    ushitapunichiakun.append(F+G);
    ushitapunichiakun.append(G+H);
    ushitapunichiakun.append(F+H);
    
    ushitapunichiakun.sort()
    
    if ushitapunichiakun[1]==ushitapunichiakun[2]:
        print(ushitapunichiakun[0])
    else:
        print(ushitapunichiakun[1])