### My issue

my code outputs the correct code, but I am getting a run time error (python)

### My code

```
# cook your dish here
def dfs(grid, r, c, size):
if r < 0 or c < 0 or r > len(grid) - 1 or c > len(grid[0]) - 1 or grid[r][c] == '0': return
grid[r][c] = '0'
size += 1
dfs(grid, r - 1, c, size)
dfs(grid, r + 1, c, size)
dfs(grid, r, c - 1, size)
dfs(grid, r, c + 1, size)
return size
t = int(input())
for _ in range(t):
N,M = map(int, input().split())
grid = [[0] * N for i in range(M)]
Chef = False
total = 0
for i in range(N):
grid[i] = list(input())
for rows in range(N):
for cols in range(M):
if grid[rows][cols] == '1':
count = dfs(grid, rows, cols, 0)
if Chef:
total += count
Chef = not Chef
print(total)
```

Learning course: Rise from 3* to 4*

Problem Link: CodeChef: Practical coding for everyone