include
include
using namespace std; int main(void){
//freopen("1122.in","r",stdin);
//freopen("1122.out","w",stdout);
int a,b,c,d,S;
scanf("%d%d%d%d%d",&a,&b,&c,&d,&S);
if(a+b==S||a+c==S||a+d==S||b+c==S||b+d==S||c+d==S){
printf("1");
}else{
printf("-1");
}
return 0;
}