#include<bits/stdc++.h>

using namespace std;

const int N=3e2+;

const int INF=0x3f3f3f3f;

int n,a[N][N];

long long ans;

void solve(int l,int r) {

    if (l==r) {

        for (int i=;i<=n;i++) for (int j=;j<=n;j++)

            if (i!=l && j!=l)

            if (a[i][j]>=INF) ans+=-; else ans+=a[i][j];

        return;

    }

    int mid=l+r>>; int b[N][N];

    memcpy(b,a,sizeof(a));

    for (int k=mid+;k<=r;k++)

        for (int i=;i<=n;i++)

            for (int j=;j<=n;j++)

                 a[i][j]=min(a[i][j],a[i][k]+a[k][j]);

    solve(l,mid);

    memcpy(a,b,sizeof(b));

    for (int k=l;k<=mid;k++)

        for (int i=;i<=n;i++)

            for (int j=;j<=n;j++)

                a[i][j]=min(a[i][j],a[i][k]+a[k][j]);

    solve(mid+,r);

}

int main()

{

    cin>>n;

    for (int i=;i<=n;i++) for (int j=;j<=n;j++) {

        scanf("%d",&a[i][j]);

        if (a[i][j]==-) a[i][j]=INF;

    }

    solve(,n);

    cout<<ans<<endl;;

    return ;

}