n,m = map(int,input().split())
a = [list(map(int,input().split())) for i in range(n)]
if n == 1: print(0); exit()
from heapq import heappop, heappush
INF = 10**15
dist = [[INF]*(m) for i in range(n)]*(n+1)
que = []
for i in range(m):
  heappush(que, (a[n-1][i],n-1, i))
  dist[n-1][i] = a[n-1][i]
while que:
  c, x,y = heappop(que)
  if c > dist[x][y]: continue
  for nxt in range(m):
    anxt = a[x][nxt]
    if dist[x][y] + anxt < dist[x][nxt]:
      dist[x][nxt] = dist[x][y] + anxt
      heappush(que,(dist[x][nxt],x,nxt))
  if x != 0:
    if dist[x][y] + a[x-1][y] < dist[x-1][y]:
      dist[x-1][y] = dist[x][y] + a[x-1][y]
      heappush(que, (dist[x-1][y], x-1, y))

print(min(dist[0]))