from heapq import *

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=[(0,0,-1)]
    while Q:
        cost,i,j=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,(Ti[k],i,k))
        else:
            alpha=cost+A[i+1][j]
            if T[i+1][j]>alpha:
                T[i+1][j]=alpha
                heappush(Q, (T[i+1][j],i+1,j))

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

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