#pragma GCC diagnostic ignored "-Wunused-variable" 
#include <bits/stdc++.h>
using namespace std;

#define BOOST
#ifdef BOOST
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using namespace boost;
using ml = multiprecision::cpp_int;
using md = multiprecision::cpp_dec_float_100;
#endif

/***** type *****/
using ll = long long;
using ld = long double;
using pll = pair<long long, long long>;
template <class T> using vt = vector<T>;
template <class T> using vvt = vector<vector<T>>;
template <class T> using vvvt = vector<vector<vector<T>>>;
/***** define *****/
#define all(c) (c).begin(), (c).end()            // begin to end
#define coutld cout << fixed << setprecision(10) // cout double
#define output(x) do{cout<<x<<endl;exit(0);}while(0)
#define rep(i, b, e) for (ll i = b; i < e; i++)  // repeat
#define repr(i, b, e) for (ll i = b; e < i; i--) // repeat reverse
#define fori(i, ...) if (ll i = -1) for(__VA_ARGS__) if (i++, 1)
#define each(i, e, c) fori (i, auto&& e: c)      // for each
/***** const value *****/
#define llong_max 9223372036854775807            // 9 * 10^18
#define ldbl_max 1.79769e+308                    // 1.7 * 10^308
#define pi 3.1415926535897932                    // 3.14 ...
/***** lambda *****/
auto Ceil = [] // if (a % b != 0) return a / b + 1;
(auto x) { return (ll)ceil(x); };
auto Count = [] // long long count value
(auto b, auto e, auto x) { return (ll)count(b, e, x); };
auto CtoL = [] // char to number
(auto c) { return (ll)c - (ll)'0'; };
auto LtoC = [] // number to char
(auto n) { return (char)('0' + n); };
auto Pow = [] // long long pow
(auto a, auto b) { return (ll)pow(a, b); };
auto Pow2 = [] // long long pow2
(auto n) { return (1LL << n); };
auto Pow10 = [] // long long pow10
(auto n) { return (ll)pow(10, n); };
auto Size = []  // long long collection size
(auto& c) { return (ll)(c).size(); };
auto Sum = [] // long long accumulate
(auto b, auto e) { return accumulate(b, e, 0LL); };

/***** operator *****/
template <class T, class S> pair<T, S> operator + (pair<T, S> l, pair<T, S> r)
{	// pair<T, S> + pair<T, S>
	return { l.first + r.first, l.second + r.second };
}
template <class T, class S> pair<T, S> operator - (pair<T, S> l, pair<T, S> r)
{	// pair<T, S> - pair<T, S>
	return { l.first - r.first, l.second - r.second };
}

/***** template *****/
template <class T> void MakeVVT
(ll ys, ll xs, vvt<T>& v, T fill = T())
{	// vector<vector<T>> resize + fill
	v.resize(ys); rep(y, 0, ys) v[y].resize(xs, fill);
}
template <class T> void MakeVVVT
(ll zs, ll ys, ll xs, vvvt<T>& v, T fill = T())
{	// vector<vector<vector<T>>> resize + fill
	v.resize(zs); rep(z, 0, zs) MakeVVT(ys, xs, v[z], fill);
}
template <class T> void InputVVT
(ll ys, ll xs, vvt<T>& v, T fix = T())
{	// input vector<vector<T>> (T != struct) + fix
	MakeVVT(ys, xs, v, fix);
	rep(y, 0, ys) rep(x, 0, xs) { cin >> v[y][x]; v[y][x] += fix; }
}
template <class T> void InputVVVT
(ll zs, ll ys, ll xs, vvvt<T>& v, T fix = T())
{	// input vector<vector<vector<T>>> (T != struct) + fix
	v.resize(zs); rep(z, 0, zs) InputVVT(ys, xs, v[z], fix);
}

/**************************************/
/********** BEGIN OF NYA LIB **********/
/**************************************/

namespace NyaGadget {}

namespace NyaGadget
{
	/***** ワーシャルフロイド法ライブラリ *****/

	struct GT_WarshallFloyd
	{	// 結果を格納する変数
		std::vector<std::vector<long long>> res;

		/**
		@brief 全点対間最短路を求める
		@param mg 隣接行列
		@param inf 存在しない辺の値
		@note
		計算量O(V^3)なので隣接行列にしか適用できない。
		存在しない経路のコストは「LLONG_MAX」を返す。
		負の閉路がある場合falseを返す。
		**/
		bool Run(const std::vector<std::vector<long long>>& mg, long long inf)
		{
			const long long INF = LLONG_MAX;
			long long vmax = (long long)mg.size();

			res = mg;
			for (auto i = 0LL; i < vmax; ++i) for (auto j = 0LL; j < vmax; ++j)
			{
				if (res[i][j] == inf) res[i][j] = INF;
			}

			for (auto k = 0LL; k < vmax; k++)
			{
				for (auto i = 0LL; i < vmax; i++)
				{
					if (res[i][k] == INF) continue;
					for (auto j = 0LL; j < vmax; j++)
					{
						if (res[k][j] == INF) continue;
						res[i][j] = std::min(res[i][j], res[i][k] + res[k][j]);

					}
				}
			}
			for (auto i = 0LL; i < vmax; i++) if (res[i][i] < 0) return false;
			for (auto i = 0LL; i < vmax; i++) res[i][i] = 0;
			return true;
		}
	};
}

/**************************************/
/*********** END OF NYA LIB ***********/
/**************************************/

using namespace NyaGadget;
//using mll = NT_ModLL< 1000000007 >;
//using mll = ModLL< 998244353 >;

int main(void)
{
	ll N; cin >> N;
	std::vector<std::vector<long long>> mg; InputVVT(N, N, mg);

	GT_WarshallFloyd wf;
	wf.Run(mg, 0LL);
	rep(i, 0, N) rep(j, 0, N) if (mg[i][j] != wf.res[i][j]) output(-1);

	rep(m, 0, N) rep(l, 0, N) rep(r, 0, N)
	{
		if (m == l || l == r || r == m) continue;
		if (mg[l][m] == 0 || mg[m][r] == 0) continue;
		if (mg[l][r] == mg[l][m] + mg[m][r]) mg[l][r] = 0;
	}

	ll ans = 0;
	rep(i, 0, N) rep(j, 0, N) ans += mg[i][j];
	cout << ans / 2;
	return 0;
}


Measured memory_bytes: 5008