#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
#pragma GCC optimize("Ofast")
#define vi vector<int>
#define vll vector<ll>
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define sc second
#define endl '\n'
#define gl ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int main()
{
int n;
cin >> n;
vi a(n);
for(int i = 0; i < n; i++) cin >> a[i];
int ans = 1;
int i = 1;
while(a[i] > a[i - 1] and i < n) i++;
while(i < n){
ans++;
if(i + 1 < n and a[i + 1] == a[i] + 1)
while(a[i + 1] == a[i] + 1 and i + 1 < n) i++;
i++;
}
cout << ans << endl;
}
