#include <bits/stdc++.h>
using namespace std;

int main()
{
	int size = 0;
	cin >> size;
	char data[size];
	for(int i = 0; i < size; i++)
	{
		cin >> data[i];
	}

	bool cond = false;

	if((size % 2) == 0)
	{
		for(int j = 0; j < (size/2); j++)
		{
			if(data[j] == data[((size - j) - 1)])
			{
				cout << j << " " << data[j] << " " << ((size - j) - 1) << " " << data[((size - j) - 1)] << " ";
				cond = true;
			}
			else
			{
				cond = false;
				j = (size/2);
			}
		}
	}
	else
	{
		for(int j = 0; j < (size/2); j++)
		{
			if(data[j] == data[((size - j) - 1)])
			{
				cout << j << " " << data[j] << " " << ((size - j) - 1) << " " << data[((size - j) - 1)] << " ";
				cond = true;
			}
			else
			{
				cond = false;
				j = (size/2);
			}
		}
	}
	cout << endl;
	if(cond)
	{
		cout << "sim" << endl;
	}
	else
	{
		cout << "nao" << endl;
	}

	cout << endl;
	return 0;
}