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# Задача 7
import math
a = float(input())
b = float(input())
c = float(input())
res = (b**2 + math.sqrt(c)) / abs(a)
print(res)

# Задача 8
n = int(input())
k = int(input())
total = n * 1200 + k * 3800
print(total)

# Задача 9
import math
a = float(input())
b = float(input())
c = float(input())
s = ((a + b) / 2) * math.sqrt(c**2 - ((a - b)**2 / 4))
print(s)