g

from sys import stdin, stdout
import math, heapq
from collections import deque

R = lambda : stdin.readline().strip()
RL = lambda f=None: list(map(f, R().split(' '))) if f else list(R().split(' '))

output = lambda x: stdout.write(str(x) + '\n')
output_list = lambda x: output(' '.join(map(str, x)))

MX = int(2e10) + 5
n = m=w= 0
a, dp1, dp2 = [], [], []

def print_arr(a):
    for i in a:
        print(*i)

def hash(x, y):
    return str(x)+'#'+str(y)

def de_hash(s):
    return list(map(int, s.split('#')))


def is_valid(i, j):
    if -1 <i < n and -1 < j < m:
        return True
    return False

def bfs(start, dp):
    q = deque()
    q.append(start)
    while len(q):
        i,j = q[0]
        q.popleft()
        for x, y in [[i+1, j], [i, j+1], [i-1, j], [i,j-1]]:
            if is_valid(x, y) and a[i][j] != -1 and dp[x][y] == MX:
                dp[x][y] = min(dp[x][y], dp[i][j] + w)
                q.append([x, y])


n, m, w = RL(int)
a = []
for i in range(n):
    a.append(RL(int))
dp1 = [ m*[MX] for i in range(n) ]
dp2 = [ m*[MX] for i in range(n) ]
dp1[0][0] =0
bfs([0, 0], dp1)
dp2[n-1][m-1] =0
bfs([n-1, m-1], dp2)
'''
print_arr(dp1)
print()
print_arr(dp2)
'''
mn1, mn2 = [MX, ''], [MX, '']
ans = MX

for i in range(n):
    for j in range(m):
        if a[i][j] > 0:
            if mn1[0] > dp1[i][j] + a[i][j]:
                mn1 = [dp1[i][j] + a[i][j], hash(i, j)]
            if mn2[0] > dp2[i][j] + a[i][j]:
                mn2 = [dp2[i][j] + a[i][j], hash(i, j)]
            ans = min(ans, dp1[i][j] + dp2[i][j])

if mn1[1] == mn2[1]:
    i, j = de_hash(mn1[1])
    ans  =  min(ans,(mn1[0]+mn2[0]-2*a[i][j]) )
else:
    ans = min(ans, mn1[0]+mn2[0])

print(ans)