#include <iostream>
#include <vector>
using namespace std;
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> liczby;
for (int i = 0; i < n; i++)
{
int pom;
cin >> pom;
liczby.push_back(pom);
}
int max_odleglosc = 0;
// sprawdzamy od lewej z ostatnim
for (int i = 0; i < n; i++)
{
if (liczby[i] != liczby[n - 1])
{
max_odleglosc = (n - 1) - i;
break;
}
}
// sprawdzamy od prawej z pierwszym
for (int i = n - 1; i >= 0; i--)
{
if (liczby[i] != liczby[0])
{
if (i > max_odleglosc)
{
max_odleglosc = i;
}
break;
}
}
if (max_odleglosc == 0)
{
cout << "BRAK";
}
else
{
cout << max_odleglosc;
}
return 0;
}
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