#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <iomanip>
using ll = long long;
using uint = unsigned int;
using graph = std::vector<std::vector<ll>>;
using wGraph = std::vector<std::vector<std::pair<ll,ll>>>;
#define rep(i,n) for (int i=0; i < int(n); i++)

using namespace std;
ll MOD7 = 1000000007;
ll MOD9 = 1000000009;
vector<ll> InputVec(ll N){
    vector<ll> A(N);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
    }
    return A;
}
void OutputVec(vector<ll> A){
    for (int i = 0; i < A.size(); ++i) {
        cout << A[i] << ",";
    }
    cout << endl;
}
vector<vector<ll>> InputVec2d(ll H,ll W){
    vector<vector<ll>> A(H);
    for (int yi = 0; yi < H; ++yi) {
        A[yi] = vector<ll>(W);
    }
    for (int yi = 0; yi < H; ++yi) {
        for (int xi = 0; xi < W; ++xi) {
            cin >> A[yi][xi];
        }
    }
    return A;
}
vector<vector<char>> InputVec2dStr(ll H,ll W){
    vector<vector<char>> A(H);
    for (int yi = 0; yi < H; ++yi) {
        A[yi] = vector<char>(W);
    }
    for (int yi = 0; yi < H; ++yi) {
        string S;
        cin >> S;
        for (int xi = 0; xi < W; ++xi) {
            A[yi][xi] = S[xi];
        }
    }
    return A;
}
void OutputVec2d(vector<vector<ll>> A){
    for (int yi = 0; yi < A.size(); ++yi) {
        for (int xi = 0; xi < A[yi].size(); ++xi) {
            cout << A[yi][xi] << ",";
        }
        cout << endl;
    }
}
graph InputGraph(ll N,ll M){
    graph G(N);
    for (int i = 0; i < M; ++i) {
        ll a,b;
        cin >> a >> b;
        a--;b--;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    return G;
}
graph InputDGraph(ll N,ll M){
    graph G(N);
    for (int i = 0; i < M; ++i) {
        ll a,b;
        cin >> a >> b;
        a--;b--;
        G[a].push_back(b);
    }
    return G;
}
wGraph InputWGraph(ll N,ll M){
    wGraph G(N);
    for (int i = 0; i < M; ++i) {
        ll a,b,c;
        cin >> a >> b >> c;
        a--;b--;
        G[a].push_back(make_pair(b,c));
        G[b].push_back(make_pair(a,c));
    }
    return G;
}
wGraph InputDWGraph(ll N, ll M){
    wGraph G(N);
    for (int i = 0; i < M; ++i) {
        ll a,b,c;
        cin >> a >> b >> c;
        a--;b--;
        G[a].push_back(make_pair(b,c));
    }
    return G;
}
void OutputGraph(graph G){
    for (int i = 0; i < G.size(); ++i) {
        cout << i << ":";
        for (int j = 0; j < G[i].size(); ++j) {
            cout << G[i][j]<< ",";
        }
        cout << endl;
    }
}

void OutputGraph(wGraph G){
    for (int i = 0; i < G.size(); ++i) {
        cout << i << ":";
        for (int j = 0; j < G[i].size(); ++j) {
            cout << G[i][j].first <<"/" << G[i][j].second << ",";
        }
        cout << endl;
    }
}

void OutputAnswerBool(bool b,bool isUpperCase = false){
    if(b){
        if(isUpperCase){
            cout << "YES" << endl;
        }else{
            cout << "Yes" << endl;
        }
    }else{
        if(isUpperCase){
            cout << "NO" << endl;
        }else{
            cout << "No" << endl;
        }
    }
}


vector<vector<ll>> Wa_Fl(wGraph G,ll N){
    vector<vector<ll>> d(N);
    for (int j = 0; j < N; ++j) {
        d[j] = vector<ll>(N);
        for (int i = 0; i < N; ++i) {
            if(j == i){
                d[j][i] = 0;
            }else{
                d[j][i] = (1ll << 50);
            }
        }
    }
    for (int i = 0; i < G.size(); ++i) {
        for (int j = 0; j < G[i].size(); ++j) {
            d[i][G[i][j].first] = G[i][j].second;
            d[G[i][j].first][i] = G[i][j].second;
        }
    }
    for (int k = 0; k < N; ++k) {
        for (int i = 0; i < N; ++i) {
            for (int j = 0; j < N; ++j) {
                if(d[i][j] > d[i][k] + d[k][j]){
                    d[i][j] = d[i][k] + d[k][j];
                    d[j][i] = d[i][k] + d[k][j];
                }
            }
        }
    }
    return d;
}


int main() {
    ll N;
    cin >> N;
    vector<pair<ll,pair<ll,ll>>> A;
    wGraph G(N);
    for (int yi = 0; yi < N; ++yi) {
        for (int xi = 0; xi < N; ++xi) {
            ll a;
            cin >> a;
            if(xi == yi){
                continue;
            }
            A.push_back(make_pair(a,make_pair(yi,xi)));
            G[yi].push_back(make_pair(xi,a));
        }
    }
    auto dG = Wa_Fl(G,N);
    sort(A.begin(),A.end());
    ll res = 0;
    for (int i = 0; i < A.size(); ++i) {
      auto current = A[i];
      ll currD = A[i].first;
      ll currA = A[i].second.first;
      ll currB = A[i].second.second;
      if(dG[currA][currB] < currD){
          cout << -1 << endl;
          return 0;
      }
      ll tmpd = 1ll << 50;
        for (int j = 0; j < N; ++j) {
            if(j == currA || j == currB){
                continue;
            }
            tmpd = min(tmpd,dG[currA][j] + dG[currB][j]);
        }
        if(tmpd > currD){
            res += currD;
        }
    }
    cout << res/2 << endl;

}


Measured memory_bytes: 7856