【April Fools Day Contest 2014G】【愚人节脑洞】On a plane 输出纵坐标平均值

G. On a plane

time limit per test
1 second

memory limit per test
256 megabytes

input
standard input

output
standard output

Input
The first line contains a single integer n (1 ≤ n ≤ 1000)
— the number of points on a plane.
Each of the next n lines
contains two real coordinates xi and yi of
the 

 point,
specified with exactly 2 fractional digits. All coordinates are between  - 1000 and 1000,
inclusive.

Output
Output a single real number θ — the
answer to the problem statement. The absolute or relative error of your answer should be at most10 - 2.

Examples

input

8
-2.14 2.06
-1.14 2.04
-2.16 1.46
-2.14 0.70
-1.42 0.40
-0.94 -0.48
-1.42 -1.28
-2.16 -1.62

output

5.410

input

5
2.26 1.44
2.28 0.64
2.30 -0.30
1.58 0.66
3.24 0.66

output

5.620

input

8
6.98 2.06
6.40 1.12
5.98 0.24
5.54 -0.60
7.16 0.30
7.82 1.24
8.34 0.24
8.74 -0.76

output

5.480

input

5
10.44 2.06
10.90 0.80
11.48 -0.48
12.06 0.76
12.54 2.06

output

6.040

input

8
16.94 2.42
15.72 2.38
14.82 1.58
14.88 0.50
15.76 -0.16
16.86 -0.20
17.00 0.88
16.40 0.92

output

6.040

input

7
20.62 3.00
21.06 2.28
21.56 1.36
21.66 0.56
21.64 -0.52
22.14 2.32
22.62 3.04

output

6.720

#include<stdio.h>
#include<iostream>
#include<string.h>
#include<string>
#include<ctype.h>
#include<math.h>
#include<set>
#include<map>
#include<vector>
#include<queue>
#include<bitset>
#include<algorithm>
#include<time.h>
using namespace std;
void fre() { freopen("c://test//input.in", "r", stdin); freopen("c://test//output.out", "w", stdout); }
#define MS(x,y) memset(x,y,sizeof(x))
#define MC(x,y) memcpy(x,y,sizeof(x))
#define MP(x,y) make_pair(x,y)
#define ls o<<1
#define rs o<<1|1
typedef long long LL;
typedef unsigned long long UL;
typedef unsigned int UI;
template <class T1, class T2>inline void gmax(T1 &a, T2 b) { if (b>a)a = b; }
template <class T1, class T2>inline void gmin(T1 &a, T2 b) { if (b<a)a = b; }
const int N = 0, M = 0, Z = 1e9 + 7, ms63 = 0x3f3f3f3f;
int n;
int main()
{
while (~scanf("%d", &n))
{
double sum = 0, x;
for (int i = 1; i <= n; ++i)
{
scanf("%*lf%lf", &x);
sum += x;
}
printf("%.3f\n", 5 + sum / n);
}
return 0;
}
/*
【trick&&吐槽】
能否想到只与第二维相关呢？
毕竟一些信息是干扰信息。常有的。

*/