include <stdio.h>;

int main() {

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;

}