import sys
# import pypyjit
import itertools
import heapq
import math
import bisect
from collections import deque, defaultdict
from functools import lru_cache, cmp_to_key


# for AtCoder Easy test
if __file__ == 'prog.py':
    pass
else:
    sys.setrecursionlimit(10 ** 6)
# pypyjit.set_param('max_unroll_recursion=-1')

input = sys.stdin.readline


def readints(): return map(int, input().split())
def readlist(): return list(readints())
def readstr(): return input()[:-1]


N, M = readints()
A = [readlist() for _ in range(N)]
if N == 1:
    print(0)
    exit()
INF = 1 << 60

dp = [[None for _ in range(M)] for _ in range(N)]
dp[0] = A[0]
for i in range(1, N):
    m = INF
    for j in range(M):
        dp[i][j] = dp[i - 1][j] + A[i][j]
        m = min(m, dp[i][j])
    for j in range(M):
        dp[i][j] = min(dp[i][j], m + A[i][j])
print(min(dp[N - 1]))