#include
using namespace std;
int increasingDecreasingSequence(int n) {
bool isDecreasing = 1;
int prev = n;
for(int i = 1; i < n; i++) {
int curr = n;
if(curr == prev)
return 0;
else if (curr > prev)
isDecreasing = 0;
else if(!isDecreasing && curr < prev)
return 0;
prev = curr;
}
return 1;
}
int main() {
int x;
cin>>x;
int n;
int count = 0;
while(x-- != 0)
{
cin >> n;
if(increasingDecreasingSequence(n) == 1)
count++;
}
if(count > 0)
cout<<"true";
else
cout<<"false";
return 0;
}