##### Short Problem Definition:

Sami’s spaceship crashed on Mars! She sends a series of `SOS`

messages to Earth for help.

##### Link

##### Complexity:

time complexity is O(N)

space complexity is O(1)

##### Execution:

We know that the message is basically a lot of concatenated SOS strings. There is no magic to this one.

##### Solution:

S = raw_input().strip() errors = 0 for i in xrange(len(S)): if i % 3 == 0 and S[i] != 'S': errors += 1 if i % 3 == 1 and S[i] != 'O': errors += 1 if i % 3 == 2 and S[i] != 'S': errors += 1 print errors

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