import sys
input = sys.stdin.readline

N,M=map(int,input().split())
A=[list(map(int,input().split())) for i in range(N)]

if N==1:
    print(0)
    exit()

DP=[0]*M
for i in range(M):
    DP[i]=A[0][i]

for i in range(1,N):
    MIN=1<<62
    for j in range(M):
        MIN=min(MIN,DP[j]+A[i][j])

    NDP=[0]*M

    for j in range(M):
        NDP[j]=min(DP[j],MIN)+A[i][j]

    DP=NDP

print(min(DP))