Hands that shed innocent blood!

There are n guilty people in a line, the i-th of them holds a claw with length L_i. The bell rings and every person kills some of people in front of him. All people kill others at the same time. Namely, the i-th person kills the j-th person if and only if j < i and j ≥ i - L_i.

You are given lengths of the claws. You need to find the total number of alive people after the bell rings.

The first line contains one integer n (1 ≤ n ≤ 10⁶) — the number of guilty people.

Second line contains n space-separated integers L₁, L₂, ..., L_n (0 ≤ L_i ≤ 10⁹), where L_iis the length of the i-th person's claw.

Print one integer — the total number of alive people after the bell rings.

4
0 1 0 10

1

2
0 0

2

10
1 1 3 0 0 0 2 1 0 3

3

In first sample the last person kills everyone in front of him.

只有右边的能杀左边的，所以最后一个不会被杀，当一个人被杀时，他也会杀死他的目标

#include<iostream>
using namespace std;
int a[100002];
int main()
{
    int n;
    int answer;
    while(cin>>n)
    {
        answer=1;
        for(int i=1;i<=n;i++)
        {
            cin>>a[i];
        }
        int chang=a[n];
        for(int i=n-1;i>=1;i--)
        {
            if(!chang)
            {
                answer++;
            }
                chang=max(chang-1,a[i]);
        }
        cout<<answer<<endl;
    }
}