3 3
1 3 1
1 5 1
4 2 1

7

n, m = map(int, input().split())
grid = [list(map(int, input().split())) for _ in range(n)]
dp = [[0]*m for _ in range(n)]
dp[0][0] = grid[0][0]
for j in range(1, m):
    dp[0][j] = dp[0][j-1] + grid[0][j]
for i in range(1, n):
    dp[i][0] = dp[i-1][0] + grid[i][0]
for i in range(1, n):
    for j in range(1, m):
        dp[i][j] = grid[i][j] + min(dp[i-1][j], dp[i][j-1])
print(dp[n-1][m-1])