#include <cstdio>
using namespace std;
#define in cin
#define out cout
struct RR
{
int w, cost;
};
RR room[2223][2223];
int main()
{
int n; scanf("%d", &n);
for(int i=1; i<=n; i++)
{
for(int j=1; j<=n; j++)
{
scanf("%d", &room[i][j].w);
room[i][j].cost = 0;
}
}
for(int i=0; i<=n; i++)
{
room[0][i].w = 300;
room[i][0].w = 300;
}
//
for(int i=2; i<=n; i++)
{
if(room[1][i-1].w <= room[1][i].w)
room[1][i].cost = room[1][i].w - room[1][i-1].w + 1;
if(room[i-1][1].w <= room[i][1].w)
room[i][1].cost = room[i][1].w - room[i-1][1].w + 1;
room[1][i].cost += room[1][i-1].cost;
room[i][1].cost += room[i-1][1].cost;
}
for(int i=2; i<=n; i++)
{
for(int j=2; j<=n; j++)
{
RR &r0 = room[i][j];
RR &r1 = room[i-1][j];
RR &r2 = room[i][j-1];
int r1c = 0;
int r2c = 0;
if(r0.w >= r1.w) r1c = r0.w - r1.w + 1;
r1c += r1.cost;
if(r0.w >= r2.w) r2c = r0.w - r2.w + 1;
r2c += r2.cost;
if(r1c < r2c) r0.cost = r1c;
else r0.cost = r2c;
}
}
printf("%d", room[n][n].cost);
return 0;
}
