include<bits/stdc++.h>

using namespace std; int main(){

int a,b,c,d,j1,j2,j3,j4,j5,j6,s;
cin>>a>>b>>c>>d>>s;
j1=a+b;
j2=a+c;
j3=a+d;
j4=b+c;
j5=b+d;
j6=c+d;
if(j1==s || j2==s || j3==s || j4==s || j5==s || j6==s){
	cout<<"1";
}
else{
	cout<<"-1";
}

}