// Original C++ solution (slower):
#include <iostream>

#include <algorithm>

#include <array>

#include <cstdint>

#include <functional>

#include <map>

#include <math.h>

#include <queue>

#include <set>

#include <stdlib.h>

#include <string>

#include <utility>

#include <vector>



#define INF 1000000000

#define MOD 1000000007

#define rep(i,a,b) for(uint32 i = (a); i < (b); ++i)

#define bitget(a,b) (((a) >> (b)) & 1)

#define ALL(x) (x).begin(),(x).end()

#define C(x) std::cout << #x << " : " << x << std::endl

#define scanf scanf_s



using int32 = std::int_fast32_t;

using int64 = std::int_fast64_t;

using uint32 = std::uint_fast32_t;

using uint64 = std::uint_fast64_t;



template<typename T>

class hashmap64 {

	std::vector<std::pair<uint64, T>> map;

	uint64 mask, count, temp;

	uint64 hash64(uint64 key) {

		key ^= key << 13;

		key ^= key >> 19;

		return key ^ (key << 17);

	}

public:

	hashmap64() :map(1024, std::make_pair(~static_cast<std::uint_fast64_t>(0), T())) {

		mask = 1023; count = 0;

	}

	hashmap64(size_t s) :map(1<<s, std::make_pair(~static_cast<std::uint_fast64_t>(0), T())) {

		mask = (1 << s) - 1; count = 0;

	}

	T &operator[](uint64 suf) {

		temp = mask&hash64(suf);

		while (~map[temp].first) {

			if (map[temp].first == suf) {

				return map[temp].second;

			}

			temp = mask&(temp + 1);

		}

		std::cerr << "?????¨????????????????????§????????????\n";

		std::abort();

	}

	void insert(uint64 key, const T &value) {

		temp = mask&hash64(key);

		while (~map[temp].first) {

			if (map[temp].first == key) {

				map[temp].second = value;

				return;

			}

			temp = mask&(temp + 1);

		}

		map[temp] = std::make_pair(key, value);

		++count;

		if ((count << 1) > mask) {

			std::pair<uint64, T> mkey;

			mask = mask << 1 | 1;

			map.resize(mask + 1, std::make_pair(~static_cast<std::uint_fast64_t>(0), T()));

			for (uint64 t = 0;t <= mask >> 1;++t) {

				if (!~map[t].first) {

					mkey = map[t];

					map[t].first = ~0;

					temp = mask&hash64(mkey.first);

					while (~map[temp].first) {

						temp = mask&(temp + 1);

					}

					map[temp] = mkey;

				}

			}

		}

		return;

	}

	bool find(uint64 key) {

		temp = mask&hash64(key);

		while (~map[temp].first) {

			if (map[temp].first == key) {

				return true;

			}

			temp = mask&(temp + 1);

		}

		return false;

	}

	bool empty(void) {

		return !count;

	}

	size_t size(void) {

		return count;

	}

};

int main(void) {

	std::ios::sync_with_stdio(false);

	std::cin.tie(0);

	hashmap64<uint32> map(19);

	uint32 n;

	std::cin >> n;

	int64 a,sum = 1e15;

	uint32 ans = 0;

	map.insert(sum, 0);

	rep(i, 0, n) {

		std::cin >> a;

		sum += a;

		if (map.find(sum)) {

			ans = std::max(ans,i+1-map[sum]);

		}

		else {

			map.insert(sum, i + 1);

		}

	}

	std::cout << ans << "\n";

	return 0;

}

// Optimized solution to the same problem (faster):
#include <iostream>

#include <algorithm>

#include <array>

#include <cstdint>

#include <functional>

#include <map>

#include <math.h>

#include <queue>

#include <set>

#include <stdlib.h>

#include <string>

#include <utility>

#include <vector>



#define INF 1000000000

#define MOD 1000000007

#define rep(i,a,b) for(uint32 i = (a); i < (b); ++i)

#define bitget(a,b) (((a) >> (b)) & 1)

#define ALL(x) (x).begin(),(x).end()

#define C(x) std::cout << #x << " : " << x << std::endl

#define scanf scanf_s



using int32 = std::int_fast32_t;

using int64 = std::int_fast64_t;

using uint32 = std::uint_fast32_t;

using uint64 = std::uint_fast64_t;



template<typename T>

class hashmap64 {

	std::vector<std::pair<uint64, T>> map;

	uint64 mask, temp, count;

	uint64 hash64(uint64 key) {

		key = ~key;

		key ^= key << 13;

		key ^= key >> 19;

		return key ^ (key << 17);

	}

public:

	hashmap64() :map(8192, std::make_pair(~static_cast<std::uint_fast64_t>(0), T())) {

		mask = 8191; count = 0;

	}

	hashmap64(size_t s) {

		s |= s << 1;

		s |= s >> 2;

		s |= s >> 4;

		s |= s >> 8;

		s |= s >> 16;

		s |= s >> 32;

		mask = s;

		count = 0;

		map.resize(s + 1, std::make_pair(~static_cast<std::uint_fast64_t>(0), T()));

	}

	T &operator[](uint64 suf) {

		temp = mask&hash64(suf);

		while (map[temp].first != suf) {

			temp = mask&(temp + 1);

		}

		return map[temp].second;

	}

	void insert(uint64 key, const T &value) {

		temp = mask&hash64(key);

		while (~map[temp].first) {

			if (map[temp].first == key) {

				map[temp].second = value;

				return;

			}

			temp = mask&(temp + 1);

		}

		map[temp] = std::make_pair(key, value);

		++count;

		if ((count << 1) > mask) {

			std::pair<uint64, T> mkey;

			uint64 t = mask;

			mask = mask << 1 | 1;

			map.resize(mask + 1, std::make_pair(~static_cast<std::uint_fast64_t>(0), T()));

			while (~map[t].first) {

				--t;

			}

			while (++t <= (mask >> 1)) {

				mkey = map[t];

				map[t].first = ~static_cast<std::uint_fast64_t>(0);

				temp = mask&hash64(mkey.first);

				while (~map[temp].first) {

					temp = mask&(temp + 1);

				}

				map[temp] = mkey;

			}

			for (t = 0;t <= mask >> 1;++t) {

				if (~map[t].first) {

					mkey = map[t];

					map[t].first = ~static_cast<std::uint_fast64_t>(0);

					temp = mask&hash64(mkey.first);

					while (~map[temp].first) {

						temp = mask&(temp + 1);

					}

					map[temp] = mkey;

				}

			}

		}

		return;

	}

	bool find(uint64 key) {

		temp = mask&hash64(key);

		while (~map[temp].first) {

			if (map[temp].first == key) {

				return true;

			}

			temp = mask&(temp + 1);

		}

		return false;

	}

	bool empty(void) {

		return !count;

	}

	size_t size(void) {

		return count;

	}

};



int main(void) {

	std::ios::sync_with_stdio(false);

	std::cin.tie(0);

	hashmap64<uint32> map(250);

	uint32 n;

	std::cin >> n;

	int64 a, sum = 1e15;

	uint32 ans = 0;

	map.insert(sum, 0);

	rep(i, 0, n) {

		std::cin >> a;

		sum += a;

		if (map.find(sum)) {

			ans = std::max(ans, i + 1 - map[sum]);

		}

		else {

			map.insert(sum, i + 1);

		}

	}

	std::cout << ans << "\n";

	return 0;

}

// Fastest known solution for this problem: