from heapq import heappop,heappush
class Heap_Point:
    def __init__(self,x,d):
        self.d=d
        self.x=x

    def __str__(self):
        return "(point:{}, dist:{})".format(self.x,self.d)

    def __repr__(self):
        return str(self)

    def __lt__(self,other):
        return self.d<other.d

    def __iter__(self):
        yield from (self.x,self.d)

#==================================================
def solve():
    N,M=map(int,input().split())
    A=[]
    for _ in range(N):
        A.append(list(map(int,input().split())))

    if N==1:
        return 0

    inf=float("inf")
    T=[[inf]*M for _ in range(N)]
    U=[inf]*N; U[0]=0

    Q=[Heap_Point((0,-1),0)]
    while Q:
        (i,j),cost=heappop(Q)

        if i==N-1:
            return cost

        if j==-1:
            Ai=A[i]; Ti=T[i]
            for k in range(M):
                if Ti[k]>cost+Ai[k]:
                    Ti[k]=cost+Ai[k]
                    heappush(Q,Heap_Point((i,k),Ti[k]))
        else:
            alpha=cost+A[i+1][j]
            if T[i+1][j]>alpha:
                T[i+1][j]=alpha
                heappush(Q, Heap_Point((i+1,j),T[i+1][j]))

            if U[i+1]>alpha:
                U[i+1]=alpha
                heappush(Q, Heap_Point((i+1,-1),U[i+1]))

#==================================================
print(solve())