---
# System prepended metadata

title: Untitled

---

## ヘロンの公式
```python=
a = int(input(""))
b = int(input(""))
c = int(input(""))
s = (a+b+c)/2
S = s*(s-a)*(s-b)*(s-c)
import math
S2 = math.sqrt(S)
print(S2)
```