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

#ifdef _RUTHEN
#include <debug.hpp>
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, M;
    cin >> N >> M;
    V<V<ll>> A(N, V<ll>(M));
    rep(i, N) rep(j, M) cin >> A[i][j];
    if (N == 1) {
        cout << 0 << '\n';
        return 0;
    }
    const ll INF = 1LL << 60;
    V<ll> dp(M, INF);
    rep(i, M) dp[i] = A[0][i];
    for (int i = 1; i < N; i++) {
        V<ll> np(M, INF);
        ll mn = *min_element(dp.begin(), dp.end());
        show(mn);
        rep(j, M) np[j] = mn + A[i - 1][j] + A[i][j];
        rep(j, M) np[j] = min(np[j], dp[j] + A[i][j]);
        swap(dp, np);
        show(dp);
    }
    ll ans = *min_element(dp.begin(), dp.end());
    cout << ans << '\n';
    return 0;
}