Submission #74072247

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Source Code Expand

// Problem: A - π
// Contest: AtCoder - AtCoder Beginner Contest 449
// URL: https://atcoder.jp/contests/abc449/tasks/abc449_a
// Memory Limit: 1024 MB
// Time Limit: 2000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

//空中散歩の SOS 僕ファー　僕ファー　僕ファー ~
#include<bits/stdc++.h>
using namespace std;
// --- Types ---
using ll = long long;
using db = double; 
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using poly = vi;

// --- Macros ---
#define fi first
#define se second
#define endl '\n'
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define unq(v) (v).erase(unique(all(v)), (v).end())

// --- Loops ---
#define rep(i, a, b) for(int i = (a); i <= (b); ++i)
#define per(i, a, b) for(int i = (a); i >= (b); --i)
#define fore(x, a) for(auto& x : a)

// --- Utils ---
template<class T> bool chmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool chmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

void solve(){
	db pi=acos(-1);
	db d;
	cin>>d;
	d/=2;
	cout<<fixed<<setprecision(9)<<d*d*pi<<endl;
	return ;
}
ll T=1;
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
//	cin>>T;
	for(ll kase=1;kase<=T;kase++){
		solve();
	}
	return 0;
}

Submission Info

Judge Result