The latest episode of 'Running Man' saw the cast members and guests Lee Seung Gi, Han Hye Jin, and SISTAR's Bora attempt to decode the mystery of the hidden numbers!

Given the hint that each of their missions contained a secret number which they had to decode, the truth behind the numbers seemed to elude everyone, with more than one contestant plunging to his or her watery doom in the final game. However, on the fourth try, resident giraffe Lee Kwang Soo answered correctly - to everyone's surprise!

Lee Kwang Soo explained his surprising braininess, revealing that when all of the mission cards were lined up end-to-end, the first letters of each card spelled out "just add one"! Combining this clue with the number they had received earlier, it was enough for him to open the locked door and secure his final prize.

The rest of the cast members were stunned at the shocking reversal of the 'giraffe', proving that Lee Kwang Soo possessed brains as well as his betrayal instinct.

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