import std.stdio, std.conv, std.functional, std.string;
import std.algorithm, std.array, std.container, std.range, std.typecons;
import std.bigint, std.numeric, std.math, std.random;
import core.bitop;

string FMT_F = "%.10f";

static File _f;
void file_io(string fn) { _f = File(fn, "r"); }
static string[] s_rd;
T _RD(T = long)() { while(!s_rd.length) s_rd = readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; }
T _RD(T = long)(File f) { while(!s_rd.length) s_rd = f.readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; }
T[] _RDA(T = long)(T fix = 0) { auto r = readln.chomp.split.to!(T[]); r[] += fix; return r; }
T[] _RDA(T = long)(File f, T fix = 0) { auto r = f.readln.chomp.split.to!(T[]); r[] += fix; return r; }
T RD(T = long)() { if (_f.isOpen) return _RD!T(_f); else return _RD!T; }
T[] RDA(T = long)(T fix = 0) { if (_f.isOpen)  return _RDA!T(_f, fix); else return _RDA!T(fix); }

size_t[] MAKE_IDX(alias less = "a < b", Range)(Range range) { auto idx = new size_t[](range.length); makeIndex!(less)(range, idx); return idx;}
size_t MIN_POS(alias less = "a < b", Range)(Range range) { auto r = minPos!(less)(range); return range.length - r.length; }

void chmin(T)(ref T x, T y) { x = min(x, y); } void chmax(T)(ref T x, T y) { x = max(x, y); }
bool inside(T)(T x, T b, T e) { return x >= b && x < e; }
long lcm(long x, long y) { return x * (y / gcd(x, y)); }

long mod = 10^^9 + 7;
//long mod = 998244353;
//long mod = 1_000_003;
void moda(ref long x, long y) { x = (x + y) % mod; }
void mods(ref long x, long y) { x = ((x + mod) - (y % mod)) % mod; }
void modm(ref long x, long y) { x = (x * y) % mod; }

void main()
{
	auto N = RD;
	auto A = new long[][](N);
	foreach (i; 0..N)
		A[i] = RDA;
	
	bool ok = true;
	(){
	foreach (y; 0..N)
	{
		foreach (x; y+1..N)
		{
			if (A[y][x] != A[x][y])
			{
				ok = false;
				return;
			}
		}
	}}();
	foreach (i; 0..N)
	{
		if (A[i][i] != 0)
		{
			ok = false;
			break;
		}
	}

	if (ok)
	{
		long ans;
		long[][] edges;
		foreach (y; 0..N)
		{
			foreach (x; y+1..N)
			{
				edges ~= [y, x, A[y][x]];
			}
		}
		edges.sort!"a[2] < b[2]"();
		(){
		foreach (e; edges)
		{
			debug writeln(e);
			auto from = e[0];
			auto to   = e[1];
			auto d    = e[2];
			long pos = -1;
			foreach (i; 0..N)
			{
				if (A[from][i] > d) continue;
				if (i == to || i == from) continue;
				auto tmp = A[from][i]+A[i][to];
				if (tmp == d)
				{
					pos = i;
				}
				else if (tmp < d)
				{
					ans = -1;
					return;
				}
			}
			debug writeln("pos:", pos);
			if (pos == -1)
			{
				ans += d;
			}
		}}();
		writeln(ans);
	}
	else
		writeln(-1);

	stdout.flush;
	debug readln;
}