学步园

大意略。

/*
ID:g0feng1
LANG:C++
TASK:beads
*/

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <vector>
#include <algorithm>
using namespace std;

FILE *fin = fopen("beads.in", "r");
FILE *fout = fopen("beads.out", "w");

const int maxn = 360;

char buf[maxn];

int n;

void read_case()
{
	fscanf(fin, "%d %s", &n, buf);
	//scanf("%d %s", &n, buf);
}

int cal()
{
	int len = strlen(buf);
	int ans = 0;
	for(int i = 0; i < n; i++)
	{
		int count = 0;
		int j = i%n, k = (i-1+n)%n;
		while(count < n && buf[j] == 'w') { count++; j = (j+1)%n; }
		char c = buf[j];
		while(count < n && (buf[j] == c || buf[j] == 'w')) { count++, j = (j+1)%n; }
		while(count < n && buf[k] == 'w') { count++; k = (k-1+n)%n; }
		c = buf[k];
		while(count < n && (buf[k] == c || buf[k] == 'w')) { count++; k = (k-1+n)%n; }
		ans = max(ans, count);
	}
	return ans;
}

void solve()
{
	read_case();
	int ans = cal();
	fprintf(fout, "%d\n", ans);
	//printf("%d\n", ans);
}

int main()
{
	solve();
	return 0;
}