#include<iostream>
#include<string>
#include<cctype>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<vector>
#include<algorithm>
#include<map>
#include<set>
#include<iomanip>
using namespace std;
#define LL long long
const int N = 1e6+10;
const int INF = 0x3f3f3f3f;
int n,a[105][105]; 
int main(){
	//freopen("","r",stdin);
	//freopen("","w",stdout);
	cin>>n;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			cin>>a[i][j];
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			if(i!=1&&j!=1)a[i][j]+=min(a[i-1][j],a[i][j-1]);
			else if(i==1&&j==1)a[i][j]=a[i][j];
			else if(i==1)a[i][j]=a[i][j-1]+a[i][j];
			else if(j==1)a[i][j]=a[i-1][j]+a[i][j];
		}
	}
	cout<<a[n][n];
	return 0;
}