#!/bin/python3
import sys
from pprint import pprint

input_f = sys.argv[1]


#########################################
#                                       #
#              Part 1                   #
#                                       #
#########################################

lines = []

with open(input_f) as file:
    for line in file:
        lines.append(int(line.rstrip()))

curr = 0
tmp = 0
prev = 0
steps=0
while curr <= len(lines)-1:
    steps+=1
    #print('Start:',lines)
    #print('Starting at index',curr,'value',lines[curr]) 
    prev = curr
    if curr+lines[curr] > len(lines)-1:
        break
    #print('Jumps from [',curr,'] =',lines[curr],'to ',end='')
    curr = lines[curr]+curr
    #print('[',curr,'] =',lines[curr])

    #print('Increment',lines[prev],end=' ')
    lines[prev] += 1
    #print('to',lines[prev])

    #print('End:',lines,'curr=',curr)    
    #input()
print(steps)
#########################################
#                                       #
#              Part 2                   #
#                                       #
#########################################

lines = []

with open(input_f) as file:
    for line in file:
        lines.append(int(line.rstrip()))


curr = 0
tmp = 0
prev = 0
steps=0

while curr <= len(lines)-1:
    steps+=1
    #print('Start:',lines)
    #print('Starting at index',curr,'value',lines[curr]) 
    prev = curr
    if curr+lines[curr] > len(lines)-1:
        break
    #print('Jumps from [',curr,'] =',lines[curr],'to ',end='')
    curr = lines[curr]+curr
    #print('[',curr,'] =',lines[curr])
    
    offset = lines[prev] #abs((lines[prev])-(lines[curr]))
    #print('Offset:',offset)
    if offset >= 3:
        #print('Decrease',lines[prev],end=' ')
        lines[prev] -= 1
    else:
        #print('Increase',lines[prev],end=' ')
        lines[prev] += 1
    #print('to',lines[prev])

    #print('End:',lines,'curr=',curr)    
    #input()
print(steps)