Jeff got 2n real numbers a1, a2, ..., a2n as a birthday present. The boy hates non-integer numbers, so he decided to slightly "adjust" the numbers he's got. Namely, Jeff consecutively executes n operations, each of them goes as follows:

  * choose indexes i and j (i ≠ j) that haven't been chosen yet; 
  * round element ai to the nearest integer that isn't more than ai (assign to ai: ⌊ ai ⌋); 
  * round element aj to the nearest integer that isn't less than aj (assign to aj: ⌈ aj ⌉). 



Nevertheless, Jeff doesn't want to hurt the feelings of the person who gave him the sequence. That's why the boy wants to perform the operations so as to make the absolute value of the difference between the sum of elements before performing the operations and the sum of elements after performing the operations as small as possible. Help Jeff find the minimum absolute value of the difference.

Input

The first line contains integer n (1 ≤ n ≤ 2000). The next line contains 2n real numbers a1, a2, ..., a2n (0 ≤ ai ≤ 10000), given with exactly three digits after the decimal point. The numbers are separated by spaces.

Output

In a single line print a single real number — the required difference with exactly three digits after the decimal point.

Examples

Input

3
0.000 0.500 0.750 1.000 2.000 3.000


Output

0.250


Input

3
4469.000 6526.000 4864.000 9356.383 7490.000 995.896


Output

0.279

Note

In the first test case you need to perform the operations as follows: (i = 1, j = 4), (i = 2, j = 3), (i = 5, j = 6). In this case, the difference will equal |(0 + 0.5 + 0.75 + 1 + 2 + 3) - (0 + 0 + 1 + 1 + 2 + 3)| = 0.25. 
	import java.io.*;
import java.util.*;

	 
	 
	public   class CODEFORCES {
		private InputStream is;
		private PrintWriter out;
		int time = 0, val[][], dp[][], DP[], start[], end[], dist[],  black[], MOD = (int)(1e9+7), arr[], weight[][], x[], y[], parent[];
		int MAX = 800000, N, K;
		long red[];
		ArrayList<Integer>[] amp;
		boolean b[], boo[][];
		Pair prr[];
		HashSet<Integer> hs = new HashSet<>();
		long Dp[][][][] = new long[110][110][12][12];
		void soln() {
			is = System.in;
			out = new PrintWriter(System.out);
			long s = System.currentTimeMillis();
			solve();
			//out.close();
			out.flush();
			//tr(System.currentTimeMillis() - s + "ms");
		}
		public static void main(String[] args) throws Exception {
			new Thread(null, new Runnable() {
			public void run() {
				try {
	 
			//new CODEFORCES().soln();
			} catch (Exception e) {
					System.out.println(e);
				}
			}
		}, "1", 1 << 26).start();
			new CODEFORCES().soln();
		}
		void solve() {
			int n = ni();
			double arr[] = new double[2*n];
			for(int i = 0; i < 2*n ;i++) arr[i] = nd();
			double sum = 0;
			int cnt = 0;
			for(double d : arr){
				if(d%1!=0){
		//			System.out.println(d);
					cnt++;
					sum += d%1;
				}
			}
		//	System.out.println(sum +" "+cnt);
			double ans = 10000;
			ans = Math.min(Math.abs(sum-cnt/2),Math.abs(sum-(cnt+1)/2));
			//if(cnt!=2*n)
			int temp = 2*n-cnt;
			double fa = ans;
			//ans = Math.min(sum%1,(1-sum%1));
			while((temp>1)){
				ans -= 1;
				ans = Math.abs(ans);
				fa = Math.min(ans, fa);
				temp-= 2;
			}
			System.out.printf("%.3f",fa);
		}	
		class Pair implements Comparable<Pair>{
			int u, v, i;
			Pair(int u, int v){
				this.u = u;
				this.v = v;
			}
			Pair(int u, int v, int i){
				this.u = u;
				this.v = v;
				this.i = i;
			}
			public int hashCode() {
				return Objects.hash();
			}
			/*public boolean equals(Object o) {
				Pair other = (Pair) o;
				return ((u == other.u && v == other.v) || (v == other.u && u == other.v));
			}*/
			public int compareTo(Pair other) {
				//return Integer.compare(val, other.val);
				return Long.compare(u, other.u) != 0 ? (Long.compare(u, other.u)) : (Long.compare(v,other.v));
			}
			public String toString(){
				return this.u +" " + this.v;
			}
		}
		int max(int a, int b){
			if(a>b) return a;
			return b;
		}
		public static class FenwickTree {
			
		    int[] array; // 1-indexed array, In this array We save cumulative information to perform efficient range queries and updates
	 
		    public FenwickTree(int size) {
		        array = new int[size + 1];
		    }
		    public int rsq(int ind) {
		        assert ind > 0;
		        int sum = 0;
		        while (ind > 0) {
		            sum += array[ind];
		            //Extracting the portion up to the first significant one of the binary representation of 'ind' and decrementing ind by that number
		            ind -= ind & (-ind);
		        }
		        return sum;
		    }
		    public int rsq(int a, int b) {
		        assert b >= a && a > 0 && b > 0;
		        return rsq(b) - rsq(a - 1);
		    }
		    public void update(int ind, int value) {
		        assert ind > 0;
		        while (ind < array.length) {
		            array[ind] += value;
		            //Extracting the portion up to the first significant one of the binary representation of 'ind' and incrementing ind by that number
		            ind += ind & (-ind);
		        }
		    }
		    public int size() {
		        return array.length - 1;
		    }
		}
		void buildGraph(int n){
			for(int i = 0; i<n ;i++){
				int x1 = ni() -1, y1 = ni()-1;
				amp[x1].add(y1);
				amp[y1].add(x1);
				x[i] = x1; y[i] = y1;
			}
		}
		long modInverse(long a, long mOD2){
	        return  power(a, mOD2-2, mOD2);
		}
		long power(long x, long y, long m)
		{
			if (y == 0)
	    return 1;
		long p = power(x, y/2, m) % m;
		p = (p * p) % m;
	 
		return (y%2 == 0)? p : (x * p) % m;
		}
		public long gcd(long a, long b){
			if(b==0) return a;
			return gcd(b,a%b);
		}
		static class ST1{
			int arr[], st[], size;
			ST1(int a[]){
				arr = a.clone();
				size = 10*arr.length;
				st = new int[size];
				build(0,arr.length-1,1);
			}
			void build(int ss, int se, int si){
				if(ss==se){
					st[si] = arr[ss];
					return;
				}
				int mid = (ss+se)/2;
				int val = 2*si;
				build(ss,mid,val); build(mid+1,se,val+1);
				st[si] = Math.min(st[val], st[val+1]);
			}
			int get(int ss, int se, int l, int r, int si){
				if(l>se || r<ss || l>r) return Integer.MAX_VALUE;
				if(l<=ss && r>=se) return st[si];
				int mid = (ss+se)/2;
				int val = 2*si;
				return Math.min(get(ss,mid,l,r,val), get(mid+1,se,l,r,val+1));
			}
		}
		static class ST{
			int arr[],lazy[],n;
			ST(int a){
				n = a;
				arr = new int[10*n];
				lazy = new int[10*n];
			}
			void up(int l,int r,int val){
				update(0,n-1,0,l,r,val);
			}
			void update(int l,int r,int c,int x,int y,int val){
				if(lazy[c]!=0){
					lazy[2*c+1]+=lazy[c];
					lazy[2*c+2]+=lazy[c];
					if(l==r)
						arr[c]+=lazy[c];
					lazy[c] = 0;
				}
				if(l>r||x>y||l>y||x>r)
					return;
				if(x<=l&&y>=r){
					lazy[c]+=val;
					return ;
				}
				int mid = l+r>>1;
				update(l,mid,2*c+1,x,y,val);
				update(mid+1,r,2*c+2,x,y,val);
				arr[c] = Math.max(arr[2*c+1], arr[2*c+2]);
			}
			int an(int ind){
				return ans(0,n-1,0,ind);
			}
			int ans(int l,int r,int c,int ind){
				if(lazy[c]!=0){
					lazy[2*c+1]+=lazy[c];
					lazy[2*c+2]+=lazy[c];
					if(l==r)
						arr[c]+=lazy[c];
					lazy[c] = 0;
				}
				if(l==r)
					return arr[c];
				int mid = l+r>>1;
				if(mid>=ind)
					return ans(l,mid,2*c+1,ind);
				return ans(mid+1,r,2*c+2,ind);
			}
		}
		public static int[] shuffle(int[] a, Random gen){
			for(int i = 0, n = a.length;i < n;i++)
			{ 
				int ind = gen.nextInt(n-i)+i; 
				int d = a[i]; 
				a[i] = a[ind];
				a[ind] = d; 
			} 
		return a; 
		}
		long power(long x, long y, int mod){
			long ans = 1;
			while(y>0){
				if(y%2==0){
					x = (x*x)%mod;
					y/=2;
				}
				else{
					ans = (x*ans)%mod;
					y--;
				}
			}
			return ans;
		}
	 
	 
		// To Get Input
		// Some Buffer Methods
		private byte[] inbuf = new byte[1024];
		public int lenbuf = 0, ptrbuf = 0;
	 
		private int readByte() {
			if (lenbuf == -1)
				throw new InputMismatchException();
			if (ptrbuf >= lenbuf) {
				ptrbuf = 0;
				try {
					lenbuf = is.read(inbuf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return -1;
			}
			return inbuf[ptrbuf++];
		}
	 
		private boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}
	 
		private int skip() {
			int b;
			while ((b = readByte()) != -1 && isSpaceChar(b))
				;
			return b;
		}
	 
		private double nd() {
			return Double.parseDouble(ns());
		}
	 
		private char nc() {
			return (char) skip();
		}
		private String ns() {
			int b = skip();
			StringBuilder sb = new StringBuilder();
			while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != '
										// ')
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}
	 
		private char[] ns(int n) {
			char[] buf = new char[n];
			int b = skip(), p = 0;
			while (p < n && !(isSpaceChar(b))) {
				buf[p++] = (char) b;
				b = readByte();
			}
			return n == p ? buf : Arrays.copyOf(buf, p);
		}
	 
		private char[][] nm(int n, int m) {
			char[][] map = new char[n][];
			for (int i = 0; i < n; i++)
				map[i] = ns(m);
			return map;
		}
	 
		private int[] na(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = ni();
			return a;
		}
	 
		private int ni() {
			int num = 0, b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}
	 
			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}
	 
		private long nl() {
			long num = 0;
			int b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}
	 
			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}
	 
		private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	 
		private void tr(Object... o) {
			if (!oj)
				System.out.println(Arrays.deepToString(o));
		}
	} 