744 B | 736 chars
# [32351: 리듬게임](https://www.acmicpc.net/problem/32351)
# Tier: Bronze 1
# Category: math, implementation, arithmetic
def get_second(bpm, duration)
60.0 / bpm * 4 * duration
end
def solve
n,s_0,k = gets.split
n = n.to_i
s_0 = s_0.to_f
k = k.to_i
l = []
prev_tm = 1
k.times do
a, b = gets.split
a = a.to_i
b = b.to_f
l << [a, b]
end
l << [n + 1, 0]
total_time = 0
current_bpm = s_0
l.each do |a, b|
duration = a - prev_tm
total_time += get_second(current_bpm, duration)
# puts get_second(current_bpm, duration)
prev_tm = a
current_bpm = b
end
total_time
end
tc = 1
# tc = gets.to_i
tc.times do |i|
# puts "Case ##{i + 1}: #{solve}"
puts "%.12f" % solve
end