I am trying to solve FLIPCOIN using python and getting runtime error? I cannot get my head around the reason.

Problem Link: https://www.codechef.com/problems/FLIPCOIN

```
def execute(coins, command):
action, a, b = command[0], int(command[2]), int(command[4])
if action == '1':
counter = 0
for i in range(a, b+1):
if coins[i] == 0:
counter += 1
print(counter)
else:
for i in range(a, b+1):
coins[i] = 1 - coins[i]
return coins
n, q = [int(x) for x in input().split()]
coins = [1] * n
for _ in range(q):
command = input()
coins = execute(coins, command)
```