#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <limits>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <functional>
#include <iomanip>

using namespace std;

#ifdef LOCAL
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define eprintf(...) 42
#endif
using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
#define reps(i, S, E) for (ll i = (S); i <= (E); i++)
#define rep(i, N) reps(i, 0, N-1)
#define deps(i, E, S) for (ll i = (E); i >= (S); i--)
#define dep(i, N) deps(i, N-1, 0)
const ll INF = 1LL << 60;
const int INF_INT = 1 << 30;

template<class T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; }return false; }
template<class T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; }return false; }
struct mll {
	static ll MOD;
	ll val;
	mll(ll v = 0) : val(v % MOD) { if (val < 0) val += MOD; }
	mll operator - () const { return -val; }
	mll operator + (const mll &b) const { return val + b.val; }
	mll operator - (const mll &b) const { return val - b.val; }
	mll operator * (const mll &b) const { return val * b.val; }
	mll operator / (const mll &b) const { return mll(*this) /= b; }
	mll operator + (ll b) const { return *this + mll(b); }
	mll operator - (ll b) const { return *this - mll(b); }
	mll operator * (ll b) const { return *this * mll(b); }
	friend mll operator + (ll a, const mll &b) { return b + a; }
	friend mll operator - (ll a, const mll &b) { return -b + a; }
	friend mll operator * (ll a, const mll &b) { return b * a; }
	mll &operator += (const mll &b) { val = (val + b.val) % MOD; return *this; }
	mll &operator -= (const mll &b) { val = (val + MOD - b.val) % MOD; return *this; }
	mll &operator *= (const mll &b) { val = (val*b.val) % MOD; return *this; }
	mll &operator /= (const mll &b) {
		ll c = b.val, d = MOD, u = 1, v = 0;
		while (d) {
			ll t = c / d;
			c -= t * d; swap(c, d);
			u -= t * v; swap(u, v);
		}
		val = val * u % MOD;
		if (val < 0) val += MOD;
		return *this;
	}
	mll &operator += (ll b) { return *this += mll(b); }
	mll &operator -= (ll b) { return *this -= mll(b); }
	mll &operator *= (ll b) { return *this *= mll(b); }
	mll &operator /= (ll b) { return *this /= mll(b); }
	bool operator == (const mll &b) { return val == b.val; }
	bool operator != (const mll &b) { return val != b.val; }
	bool operator == (ll b) { return *this == mll(b); }
	bool operator != (ll b) { return *this != mll(b); }
	friend bool operator == (ll a, const mll &b) { return mll(a) == b.val; }
	friend bool operator != (ll a, const mll &b) { return mll(a) != b.val; }
	friend ostream &operator << (ostream &os, const mll &a) { return os << a.val; }
	friend istream &operator >> (istream &is, mll &a) { return is >> a.val; }
	static mll Combination(ll a, ll b) {
		chmin(b, a - b);
		if (b < 0) return mll(0);
		mll c = 1;
		rep(i, b) c *= a - i;
		rep(i, b) c /= i + 1;
		return c;
	}
};
using vmll = std::vector<mll>;
using vvmll = std::vector<vmll>;
using vvvmll = std::vector<vvmll>;
using vvvvmll = std::vector<vvvmll>;

struct Fast {
	Fast() {
		cin.tie(0);
		ios::sync_with_stdio(false);
		cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
	}
} fast; //cin,cout高速化のおまじない＋桁数指定

ll mll::MOD = (ll)(1e9 + 7);// 998244353ll;


struct LLPair {
	ll a = 0;
	ll b = 0;
	ll c = 0;
	LLPair() {}
	LLPair(ll a, ll b, ll c) {
		this->a = a;
		this->b = b;
		this->c = c;
	}
};

int main() {
	ll N;
	cin >> N;
	vvll graph(N, vll(N, INF)); //N頂点の隣接行列
	rep(i, N) rep(j, N) {
		cin >> graph[i][j];
	}

	//◆--↓--全頂点間の距離を求めるワーシャルフロイド法:O(N^3)--↓--
	//vvll dist(N, vll(N, INF));
	//rep(j, N) rep(i, N) {
	//	if (i == j) {
	//		dist[i][j] = 0;
	//	}
	//	else {
	//		dist[j][i] = graph[j][i];
	//	}
	//}

	////全頂点間の距離を求めるO(N^3)
	//rep(i, N) rep(j, N) rep(k, N) { // 経由する頂点-開始頂点-終端
	//	if (dist[j][i] == INF || dist[i][k] == INF) { //負の距離が含まれている場合は必要
	//		continue;
	//	}
	//	dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
	//}
	//--↑--ワーシャルフロイド--↑--

	vector<LLPair> e(0);
	reps(i, 0, N - 1) reps(j, i + 1, N - 1) {
		e.emplace_back(LLPair(i, j, graph[i][j]));
	}
	std::sort(e.begin(), e.end(), [](const LLPair &a, const LLPair &b) {
		return a.c > b.c; //降順にするには > とする
	});

	ll numEdge = (ll)e.size();
	ll result = 0;
	rep(i, numEdge) {
		bool needed = true;

		//e[i].a -> e[i].b のコストと、他の任意のノードを経由するコストを比較
		rep(j, N) {
			if (j == e[i].a || j == e[i].b) {
				continue;
			}

			if (graph[e[i].a][j] == INF || graph[j][e[i].b] == INF) {
				continue;
			}

			ll cost = graph[e[i].a][j] + graph[j][e[i].b];

			if (graph[e[i].a][e[i].b] == cost) {
				//取り除きOK
				needed = false;
				break;
			}
			else if (graph[e[i].a][e[i].b] < cost){
				//必要
			}
			else {
				//矛盾
				cout << -1 << endl;
				return 0;
			}
		}

		if (needed) {
			result += graph[e[i].a][e[i].b];
		}
		else {
			graph[e[i].a][e[i].b] = INF;
			graph[e[i].b][e[i].a] = INF;
		}
	}

	cout << result << endl;

	return 0;
}

Measured memory_bytes: 2684