401637: GYM100503 E Meetings

Two cities A and B are connected by a straight road that is exactly l meters long. At the initial moment of time a cyclist starts moving from city A to city B at a speed v₁ meters/second, and a pedestrian starts moving from city B to city A at a speed v₂ meters/second. When one of them reaches a city, the road ends, so the person has to turn around and start moving in the opposite direction by the same road, keeping the original speed. As a result, the cyclist and the pedestrian are traveling between cities A and B indefinitely.

Your task is to calculate the number of times they will meet during the first t seconds. If they meet in exactly t seconds after the initial moment of time, this meeting should also be counted.

The only line of input contains four integer numbers: l, v₁, v₂ and t. All numbers are between 1 and 10⁹, inclusively.

Print a single integer — the number of times the cyclist and the pedestrian will meet during the first t seconds.

1000 10 1 200

2

4 4 3 4

4