#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const long long INF = 1LL<<60;
vector<vector<ll>> dp(1006, vector<ll>(1006, INF));

int main() {
    int N, M; cin >> N >> M;
    ll a[N][M];
    for(int i = 0; i < N; i++){
        for(int j = 0; j < M; j++) {
            cin >> a[i][j];
        }
    }
    for(int i = 0; i < M; i++) {
    if(N == 1) {
        cout << 0 << endl;
        return 0;
    }
        dp[0][i] = a[0][i];
    }
    for(int i = 1; i < N; i++) {
        int midx = -1;
        ll mval = INF;
        for(int j = 0; j < M; j++) {
            if(dp[i-1][j] < mval) {
                mval = dp[i-1][j];
                midx = j;
            }
        }
        for(int j = 0; j < M; j++) {
            dp[i][j] = min({dp[i][j], dp[i-1][j] + a[i][j], mval + a[i-1][j] + a[i][j]});
        }
    }
    ll ans = INF;
    for(int i = 0; i < M; i++) {
        ans = min(ans, dp[N-1][i]);
    }
    cout << ans << endl;
}