#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}
int main() {
	int64_t x;
	std::cin >> x;
	for (int64_t i = std::max<int64_t>(0, x - 60); i <= x + 60; i++) {
		if ((i ^ __builtin_popcountll(i)) == x) {
			printf("%" PRId64 "\n", i);
			return 0;
		}
	}
	puts("-1");
	
	return 0;
}