#include <bits/stdc++.h>

using namespace std;
const int INF = 0x3f3f3f3f;

const int N = 110;
int a[N][N];
int n, m;
int res = INF;
// dfs解法
/*
2 3
1 3 5
2 4 6


答案：
13

2 3
1 2 3
4 5 6
*/
int dx[] = {1, 0};
int dy[] = {0, 1};
void dfs(int x, int y, int sum) {
    if (x == n && y == m) {
        res = min(res, sum);
        return;
    }
    for (int i = 0; i < 2; i++) {
        int tx = x + dx[i], ty = y + dy[i];
        if (tx > n || ty > m) continue;
        dfs(tx, ty, sum + a[tx][ty]);
    }
}
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            cin >> a[i][j];

    dfs(1, 1, a[1][1]);
    printf("%d\n", res);
    return 0;
}