#include <iostream>
#include <cstdio>
#include <algorithm>
 
int n;
char s[355];
 
int md(int j) {
	while(j<0) j+=n;
	return j%n;
}
 
int bp(int pos, int dir) {
	int i, j;
	char col='w';
	if(dir==1) j=pos;
	else j=pos-1;
	for(i=0; i<n; i++, j=md(j+dir)) {
		if(col=='w' && s[j]!='w') col=s[j];
		if(col!='w' && s[j]!='w' && s[j]!=col) break;
	}
	return i;
}
 
int main() {
	int ma=0;
	scanf("%d", &n);
	scanf("%s", s);
	for(int i=0; i<n; i++) ma=std::max(bp(i, -1)+bp(i, 1), ma);
	if(ma>n) ma=n;
	printf("%d\n", ma);
	return 0;
}

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MTAKYndycnJyYmJicg==

10
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