#include <bits/stdc++.h>

using namespace std;

const int N = 110;

int n;
int w[N][N], f[N];

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            cin >> w[i][j];

    // 初始化为最大值
    memset(f, 0x3f, sizeof f);

    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++) {
            if (i == 1 && j == 1)
                f[j] = w[i][j];
            else
                f[j] = min(f[j], f[j - 1]) + w[i][j];
        }
    printf("%d\n", f[n]);
    return 0;
}