#include <bits/stdc++.h>
using namespace std;

int main()
{
    int N, M;
    cin >> N >> M;
    vector<vector<int>> A(N, vector<int>(M));
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < M; j++)
        {
            cin >> A[i][j];
        }
    }
    reverse(A.begin(), A.end());
    vector<vector<long long>> dp(N + 1, vector<long long>(M));
    for (int i = 1; i <= N; i++)
    {
        for (int j = 0; j < M; j++)
        {
            dp[i][j] = dp[i - 1][j] + A[i - 1][j];
        }
        long long two = 2e18;
        for (int j = 0; j < M; j++)
        {
            two = min(two, dp[i - 1][j] + A[i - 1][j]);
        }
        for (int j = 0; j < M; j++)
        {
            dp[i][j] = min(dp[i][j], two + A[i - 1][j]);
        }
    }
    long long ans = 2e18;
    for (int i = 0; i < M; i++)
    {
        ans = min(ans, dp[N][i]);
    }
    if (N == 1)
    {
        ans = 0;
    }
    cout << ans;
}