/*
ID: cm750621
PROG: beads
LANG: C++
*/
#include<stdio.h>
char p[1200];
int main(){
freopen("beads.in","r",stdin);
freopen("beads.out","w",stdout);
int i,j,k,m,n,s=2;
scanf("%d\n",&n);
for(i=400;i<400+n;i++){
scanf("%c",&p[i]);
p[i+n]=p[i];
p[i-n]=p[i];
}
for(i=400;i<400+n;i++){
j=1;
k=1;
while((p[i-1]==p[i-1-j]||p[i-j-1]=='w'||p[i-1]=='w')&&j<=n-2){
if(p[i-1]=='w')
p[i-1]=p[i-1-j];
j++;
}
while((p[i]==p[i+k]||p[i+k]=='w'||p[i]=='w')&&j+k<=n-1){
if(p[i]=='w')
p[i]=p[i+k];
k++;
}
if(s<j+k)
s=j+k;
}
printf("%d\n",s);
return 0;
}