Problem:
Score : 300 points

Problem Statement

There are N people standing in a row from west to east.
Each person is facing east or west.
The directions of the people is given as a string S of length N.
The i-th person from the west is facing east if S_i = E, and west if S_i = W.

You will appoint one of the N people as the leader, then command the rest of them to face in the direction of the leader.
Here, we do not care which direction the leader is facing.

The people in the row hate to change their directions, so you would like to select the leader so that the number of people who have to change their directions is minimized.
Find the minimum number of people who have to change their directions.

Constraints

2 \leq N \leq 3 \times 10^5

|S| = N

S_i is E or W.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print the minimum number of people who have to change their directions.

Sample Input 1

5
WEEWW

Sample Output 1

1

Assume that we appoint the third person from the west as the leader.
Then, the first person from the west needs to face east and has to turn around.
The other people do not need to change their directions, so the number of people who have to change their directions is 1 in this case.
It is not possible to have 0 people who have to change their directions, so the answer is 1.

Sample Input 2

12
WEWEWEEEWWWE

Sample Output 2

4

Sample Input 3

8
WWWWWEEE

Sample Output 3

3

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#define _USE_MATH_DEFINES
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <limits.h>    
#define inf 100000000
#define INF 9223372036854775807
#define EPS 1e-10
#define sq(n) ((n)*(n))
#define rep(i,n) for(i=0;i<n;i++)
#define rev(i,n) for(i=n-1;i>=0;i--)
#define sort(a,n) qsort(a,n,sizeof(TYPE),cmp)
#define sort_r(a,n) qsort(a,n,sizeof(TYPE),cmp_r);
#define chsort(s,n) qsort(s,n,sizeof(char),cmp)
#define chsort_r(s,n) qsort(s,n,sizeof(char),char_cmp_r);
#define TYPE int
#define MEMSET(a) memset(a,0,sizeof(a))
int mod=(int)1e09+7;

int in(void){
    int i;scanf("%d",&i);
    return i;
}
long long llin(void){
    long long i;scanf("%lld",&i);
    return i;
}
double din(void){
    double i;scanf("%lf",&i);
    return i;
}
void chin(char s[]){
    scanf("%s",s);
}
void print(int a){
    printf("%d\n",a);
}
void llprint(long long a){
    printf("%lld\n",a);
}
void dprint(double a){
    printf("%.10f\n",a);
}
void print2(int a,int b){
    printf("%d %d\n",a,b);
}
long long max(long long a,long long b){
    return a>b?a:b;
}
long long min(long long a,long long b){
    return a<b?a:b;
}
int cmp(const void *a,const void *b){
    return *(TYPE *)a-*(TYPE *)b;
}
int cmp_r(const void *a,const void *b){
    return *(TYPE *)b-*(TYPE *)a;
}
int char_cmp(const void *a,const void *b){
    return strcmp((char *)a,(char *)b);
}
int char_cmp_r(const void *a,const void *b){
    return strcmp((char *)b,(char *)a);
}
void swap(int *a,int *b){
    int t=*a;
    *a=*b;
    *b=t;
}
long long gcd(long long x,long long y){
    return x%y?gcd(y,x%y):y;
}
long long lcm(long long x,long long y){
    return x/gcd(x,y)*y;
}

// write codes below this
// when you use 'sort',
// make sure TYPE macro is correct
int w[3*100000],e[3*100000];
char s[3*100000];
int main(void){
    int n=in(),i,j,ans=inf,ec=0,wc=0;
    chin(s);
    rep(i,n)if(s[i]=='E')ec++;
    rep(i,n){
        if(s[i]=='E'){
            e[i]=--ec;
            w[i]=wc;
        }
        else{
            e[i]=ec;
            w[i]=wc++;
        }
    }
    rep(i,n)ans=min(ans,e[i]+w[i]);
    print(ans);
    return 0;
}