Ivan recently bought a detective book. The book is so interesting that each page of this book introduces some sort of a mystery, which will be explained later. The ii-th page contains some mystery that will be explained on page aiai (ai≥iai≥i).
Ivan wants to read the whole book. Each day, he reads the first page he didn't read earlier, and continues to read the following pages one by one, until all the mysteries he read about are explained and clear to him (Ivan stops if there does not exist any page ii such that Ivan already has read it, but hasn't read page aiai). After that, he closes the book and continues to read it on the following day from the next page.
How many days will it take to read the whole book?
Input
The first line contains single integer nn (1≤n≤1041≤n≤104) — the number of pages in the book.
The second line contains nn integers a1,a2,…,ana1,a2,…,an (i≤ai≤ni≤ai≤n), where aiai is the number of page which contains the explanation of the mystery on page ii.
Output
Print one integer — the number of days it will take to read the whole book.
Example
Input
9 1 3 3 6 7 6 8 8 9
Output
4
Note
Explanation of the example test:
During the first day Ivan will read only the first page. During the second day Ivan will read pages number 22 and 33. During the third day — pages 44-88. During the fourth (and the last) day Ivan will read remaining page number 99.
题目含义：求从后往前找前缀最大的数和坐标下坠的相同的有几个
思路：for循环max1记录最大判断下表是否相同
代码：
#include<iostream>
using namespace std;
int a[1000009];
int main()
{
int n;
scanf("%d",&n);
for(int i=1;i<=n;++i)
{
scanf("%d",&a[i]);
}
int r=0,max1=0;
for(int i=1;i<=n;++i)
{
if(max1<a[i])
{
max1 = a[i];//更新最大值
}
if(max1 == i)
{
r++;//最大值和坐标相同r++
}
}
printf("%d\n",r);//输出r
return 0;
}