// dfmt off
T lread(T=long)(){return readln.chomp.to!T;}T[] lreads(T=long)(long n){return iota(n).map!((_)=>lread!T).array;}
T[] aryread(T=long)(){return readln.split.to!(T[]);}void arywrite(T)(T a){a.map!text.join(' ').writeln;}
void scan(L...)(ref L A){auto l=readln.split;foreach(i,T;L){A[i]=l[i].to!T;}}alias sread=()=>readln.chomp();
void dprint(L...)(lazy L A){debug{auto l=new string[](L.length);static foreach(i,a;A)l[i]=a.text;arywrite(l);}}
static immutable MOD=10^^9+7;alias PQueue(T,alias l="b<a")=BinaryHeap!(Array!T,l);import std, core.bitop;
// dfmt on

void main()
{
    long N = lread();
    auto A = new long[][](N);
    foreach (i; 0 .. N)
        A[i] = aryread();

    long ans;
    auto B = new long[][](N, N);
    foreach (i; 0 .. N)
        foreach (j; i + 1 .. N)
        {
            ans += A[i][j];
            foreach (k; 0 .. N)
            {
                if (i == k || j == k)
                    continue;
                if (A[i][j] == A[i][k] + A[k][j])
                {
                    ans -= A[i][j];
                }
                if (A[i][k] + A[k][j] < A[i][j])
                {
                    writeln(-1);
                    return;
                }
            }
        }
    writeln(ans);
}
