int a[101][101],b[101];

bool v[101];

int ans,n;

int main()

{

scanf("%d",&n);

for (int i=1;i<=n;i++)

for (int j=1;j<=n;j++)

{

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

if (a[i][j]==0) a[i][j]=0x7f7f7f7f7f;

}

for (int i=1;i<=n;i++) b[i]=a[1][i];

v[1]=1;

while (1)

{

int k=0,min=0x7f7f7f7f7f;

for (int i=1;i<=n;++i)

if (b[i]<min&&!v[i])

{

min=b[i];

k=i;

}

if (k==0) break;

v[k]=1;

ans+=b[k];

for (int i=1;i<=n;i++)

if (!v[i]&&a[k][i]<b[i])

b[i]=a[k][i];

}

printf("%d",ans);

return 0;

}