include <stdio.h>

int main() {

int a,b,c,d,s;
//scanf("%d %d %d %d %d",&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)||(c+b==s)||(d+b==s)||(c+d==s))
{
	printf("1");
}
else
{
	printf("-1");
}
return 0;

}