#include<......>
#define int long long
#define fo(i,a,b) for(int i=a;i<=b;i++)
using namespace std;
int n,m,ans=INT_MAX;
int a[101][101],f[101][101];
main(){
	memset(f,0x3f,sizeof(a));
	cin>>n;
	fo(i,1,n){
		fo(j,1,n){
			cin>>a[i][j];
		}
	}
	f[1][1]=a[1][1];
	fo(i,1,n){
		fo(j,1,n){
			if(i==1&&j==1) continue;
			f[i][j]=min(f[i-1][j],f[i][j-1])+a[i][j];
		}
	}
	cout<<f[n][n];
	return 0;
}