def main():
    from sys import stdin, setrecursionlimit
    # setrecursionlimit(1000000)
    input = stdin.readline
    def iinput(): return int(input())
    def sinput(): return input().rstrip()
    def i0input(): return int(input()) - 1
    def linput(): return list(input().split())
    def liinput(): return list(map(int, input().split()))
    def miinput(): return map(int, input().split())
    def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
    def mi0input(): return map(lambda x: int(x) - 1, input().split())
    INF = 1000000000000000000
    MOD = 1000000007

    N, M = miinput()
    A = []
    for _ in [0] * N:
        A.append(liinput())
    
    if N == 1:
        print(0)
        return
    
    dp = [INF] * N
    dp[0] = 0
    
    for i in range(1, N):
        for j in range(M):
            A[i][j] += A[i-1][j]
            dp[i] = min(dp[i], A[i][j])
            for k in range(i-1):
                dp[i] = min(dp[k+1] + A[i][j] - A[k][j], dp[i])

    print(dp[-1])

main()