#include<iostream>
#include<algorithm>
using namespace std;
int n,w[105][105],f[105][105],i,j;
int main()
{
scanf("%d",&n);
for(i=1;i<=n;i++)for(j=1;j<=n;j++)scanf("%d",&w[i][j]);
for(i=1;i<=n;i++)for(j=1;j<=n;j++)
if(i==1&&j==1)f[i][j]=w[i][j];
else{
f[i][j]=1e9;
if(i>1)f[i][j]=min(f[i][j],f[i-1][j]+w[i][j]);
if(j>1)f[i][j]=min(f[i][j],f[i][j-1]+w[i][j]);
}
printf("%d\n",f[n][n]);
return 0;
}