#include <iostream>
using namespace std;
#define ll unsigned long long int
bool isSorted(ll arr[], ll n) {
if (n == 0 || n == 1) {
return true;
}
if (arr[0] < arr[1] and isSorted(arr + 1, n - 1)) {
return true;
}
return false;
}
int main() {
ll n;
cin >> n;
ll arr[n];
for (ll i = 0; i < n; i++) {
cin >> arr[i];
}
if (isSorted(arr, n)) {
cout << "true" << endl;
} else {
cout << "false" << endl;
}
}