#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
bool IsSequence(int seq[],int len)
{
if(seq == NULL || len<1)
return false;
int i;
int end_data = seq[len-1];
for(i=0;i<len-1;i++)
{
if(seq[i]>end_data)
break;
}
int RightStart = i;
for(;i<len-1;i++)
{
if(seq[i]<end_data)
return false;
}
bool left =true,right = true;
if(RightStart>0)
left = IsSequence(seq,RightStart);
if(RightStart<len-1-RightStart)
right = IsSequence(seq+i,len-1-RightStart);
return (right&&left);
}
int main(void)
{
int n=0,i;
printf("len is ");
scanf("%d",&n);
int str[10]={0};
for(i=0;i<n;i++)
{
scanf("%d",&str[i]);
}
printf("%d",IsSequence(str,n));
return 0;
}