#include<bits/stdc++.h>
using namespace std;
int a[2005][2005];
int main()
{
	int n, m,ans;
	cin >> m >> n;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			cin >> a[i][j];
	for (int j = m ; j >= 1; j--)
		for (int i = 1; i <= n; i++)
			a[i][j] += min(a[i][j + 1], a[i % n + 1][j + 1]);
	for (int i = 1; i <= n; i++)
		ans = min(ans, a[i][1]);
	cout << ans << endl;
	return 0;
}