Problem:
Score : 200 points

Problem Statement

Snuke lives on an infinite two-dimensional plane. He is going on an N-day trip.
At the beginning of Day 1, he is at home. His plan is described in a string S of length N.
On Day i(1 ≦ i ≦ N), he will travel a positive distance in the following direction:

North if the i-th letter of S is N

West if the i-th letter of S is W

South if the i-th letter of S is S

East if the i-th letter of S is E

He has not decided each day's travel distance. Determine whether it is possible to set each day's travel distance so that he will be back at home at the end of Day N.

Constraints

1 ≦ | S | ≦ 1000

S consists of the letters N, W, S, E.

Input

The input is given from Standard Input in the following format:

S

Output

Print Yes if it is possible to set each day's travel distance so that he will be back at home at the end of Day N. Otherwise, print No.

Sample Input 1

SENW

Sample Output 1

Yes

If Snuke travels a distance of 1 on each day, he will be back at home at the end of day 4.

Sample Input 2

NSNNSNSN

Sample Output 2

Yes

Sample Input 3

NNEW

Sample Output 3

No

Sample Input 4

W

Sample Output 4

No

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using static Atcoder;
using System.Threading.Tasks;
using System.ComponentModel;

public class Hello
{
    private const int INF = 1000000007;
    public static void Main()
    {
        string S = Console.ReadLine();
        if ((S.Contains("N") && !S.Contains("S")) ||
            (S.Contains("S") && !S.Contains("N")) ||
            (S.Contains("E") && !S.Contains("W")) ||
            (S.Contains("W") && !S.Contains("E"))) Console.WriteLine("No");
        else Console.WriteLine("Yes");
    }
}

public class Factorization
{
    private static long N;

    public Factorization(long n) { N = n; }

    //最大公約数を返す
    public static long GCD(long a, long b)
    {
        if (a < b) return GCD(b, a);
        long r;
        while (b != 0)
        {
            r = a % b;
            a = b;
            b = r;
        }
        return a;
    }

    //素数判定
    public static bool IsPrime(long n)
    {
        if (n < 2) return false;
        if (n == 2) return true;
        if (n % 2 == 0) return false;

        double root = Math.Sqrt(n);
        for (int i = 3; i <= root; i += 2)
        {
            if (n % i == 0) return false;
        }
        return true;
    }

    //試し割り
    private static int[] TryPrimes = new int[] { 2, 3, 5, 7, 11 };
    public long TryAllocation(long p)
    {
        long count = 0;
        while (N % p == 0)
        {
            count++;
            N /= p;
        }
        return count;
    }

    private int[] xi = new int[] { 13, 17, 19, 23, 29 };
    private long f(long x, int suffix)
    {
        return (xi[suffix % xi.Count()] * x + suffix) % N;
    }

    //nを分解
    public long PollardsRho(long n, int suffix = 0)
    {
        //素数を渡すと失敗するらしい
        if (IsPrime(n)) return n; //もう素数
        long x = 2, y = 2, d = 1;
        while (d == 1)
        {
            x = f(x, suffix);
            y = f(f(y, suffix), suffix);
            d = GCD(Math.Abs(x - y), n);
        }
        if (d == n)
        {
            //f(x)を変えて試す
            return PollardsRho(n, suffix + 1);
        }
        return d;
    }

    public IEnumerable<long> Calc()
    {
        //小さな素因数の計算
        foreach (var prime in TryPrimes)
        {
            var box = TryAllocation(prime);
            for (int i = 0; i < box; i++) yield return prime;
        }

        //残りをRhoで解く
        while (true)
        {
            if (N == 1) break;
            var ret = PollardsRho(N);
            yield return ret;
            N /= ret;
        }
    }
}


public class Atcoder
{
    static void Swap<T>(ref T a, ref T b)
    {
        var t = a;
        a = b;
        b = t;
    }
    public static int LCM(int a, int b)
    {
        int c = a * b;
        if (a < b) Swap(ref a, ref b);
        int d = a % b;
        while (d != 0)
        {
            a = b;
            b = d;
            d = a % b;
        }
        return c / b;
    }
    public static string StrReverce(string s)
    {
        return new string(s.Reverse().ToArray());
    }
    public static int IntRead()
    {
        return int.Parse(Console.ReadLine());
    }
    public static bool IsPrime(int n)
    {
        if (n < 2) return false;
        if (n == 2) return true;
        if (n % 2 == 0) return false;

        //double sqrtNum = Math.Sqrt(n);
        for (int i = 3; i < n; i += 2)
        {
            if (n % i == 0) return false;
        }
        return true;
    }
    public static string[] SpRead(char c)
    {
        return Console.ReadLine().Split(c);
    }
    public static long[] LSRead()
    {
        return Console.ReadLine().Split(' ').Select(long.Parse).ToArray();
    }
    public static long Combination(int n, int r)
    {
        if (n == r) return 1;
        return
            Enumerable.Range((n - r + 1), r).ToList().Aggregate((now, next) => now * next) /
            Enumerable.Range(1, r).ToList().Aggregate((now, next) => now * next);
    }
    public static long Permutation(int n, int r)
    {
        if (n == r) return 1;
        return
            Enumerable.Range((n - r), r).ToList().Aggregate((now, next) => now * next);
    }
    public static long LongRead()
    {
        return long.Parse(Console.ReadLine());
    }
    public static long[] LongLine()
    {
        return Console.ReadLine().Split(' ').Select(long.Parse).ToArray();
    }
}