#include <iostream>
#include <cstdint>
#include <vector>

static inline constexpr const char* solve(const uint_fast32_t N, const std::vector<uint_fast32_t>& A) noexcept
{
	for (uint_fast32_t i = 0; i != N; ++i)
		if (A[i] != 0) return "Yes";

	return "No";
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	uint_fast32_t N, i;
	std::cin >> N;
	std::vector<uint_fast32_t> A(N);
	for (i = 0; i != N; ++i)
		std::cin >> A[i];

	std::cout << solve(N, A) << '\n';
	return 0;
}