#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n; 
    scanf("%d",&n);
    int *m = malloc(sizeof(int) * n);
    for(int m_i = 0; m_i < n; m_i++){
       scanf("%d",&m[m_i]);
    }
    // your code goes here
    // scan through input til out of order. 2^(n-1) where n is in-order amt
    int i = 0;
    while(i + 1 < n && m[i] < m[i + 1])
        i++;
    printf("%.f\n", pow(2, i));
    return 0;
}