Hands that shed innocent blood!

There are *n* guilty people in a line, the *i*-th of them holds a claw with length *L*<sub class="lower-index">*i*</sub>. 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* &lt; *i* and *j* ≥ *i* - *L*<sub class="lower-index">*i*</sub>.

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* ≤ 10<sup class="upper-index">6</sup>) — the number of guilty people.

Second line contains *n* space-separated integers *L*<sub class="lower-index">1</sub>, *L*<sub class="lower-index">2</sub>, ..., *L*<sub class="lower-index">*n*</sub> (0 ≤ *L*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">9</sup>), where *L*<sub class="lower-index">*i*</sub> is the length of the *i*-th person's claw.
In first sample the last person kills everyone in front of him.
4
0 1 0 10
1
2
0 0
2
10
1 1 3 0 0 0 2 1 0 3
3
10
0 0 2 0 0 3 3 2 2 0
2
1
0
1
5
0 0 0 1 0
4
6
3 1 1 0 3 3
1
8
0 0 0 1 0 0 1 2
5
1
1000000000
1
2
1 3
1
2
1000000000 1000000000
1
11
1 0 0 1 1 3 2 0 0 2 3
4
1
1
1
n=int(input())
l=list(map(int,input().split()))
t1=0
s=[]
kt=False
d=0
for i in range (1,n):
    '''if (l[i]<i-t1): 
         s.append (i)
         t1=i
         kt=True
    else : 
        if (kt==True)  :
            k=s[-1]
            while (k>=i-l[i]) and (len(s)!=0):
                s.pop()
                if len(s)!=0: k=s[-1]
        else:s.append(i)
        kt=False
        t1=i'''
    '''if (l[i]>=i-t1) (i-l[i]<=i-t1) (i-l[i]>i-t1): 
        d+=i-l[i]   
        t1=i  '''
    if  (l[i]>=i-t1) : 
        d+=i-t1
        t1=i
    if  (l[i]<i-t1) and (l[i]!=0) :
        d+=l[i]
        t1=i
print (n-d)
