Codeforces 892B. Wrath

B. Wrath

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Hands that shed innocent blood!

There are n guilty people in a line, the i-th of them holds a claw with length Li. 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 - Li.

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

Input

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

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

Output

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

Examples

input

40 1 0 10

output

1

input

20 0

output

2

input

101 1 3 0 0 0 2 1 0 3

output

3

Note

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

题目大意：几个人互相杀人，只要排在他前面而且前面那个人的下标大于等于自己的下标减去L[i]就可以杀，问最后剩多少人

#include<bits/stdc++.h>using namespace std;const int maxn=1e6+7;int num[maxn];int main(){int n;scanf("%d",&n);for(int i=1;i<=n;i++){scanf("%d",&num[i]);}int ans=0;int tmp=n+1;for(int i=n;i>=1;i--){if(i<tmp) ans++;if(tmp>=i-num[i]) tmp=i-num[i];}printf("%d\n",ans);}