In the question given below, a set of four sentences P, Q, R & S is given, which when properly sequenced, form a coherent paragraph. Arrange the sentences in the correct order and mark the correct order as your answer.

P. The confrontation is often considered the closest the Cold War came to be escalated into a full-scale nuclear war.

Q. After several days of tense negotiations, an agreement was reached between John F. Kennedy and Khrushchev to ease the tensions.

R. It was initiated by the American discovery of ballistic missile deployment in Cuba by the Soviet Union.

S. The Cuban Missile Crisis was a 13-day confrontation between the United States and the Soviet Union.