#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

inline int power(int a, int b, int mod=M) {
    int x = 1;
    a %= mod;
    while (b) {
        if (b & 1) x = (x * a) % mod; 
        a = (a * a) % mod;
        b >>= 1;
    }
    return x;
}


//_ ***************************** START Below *******************************




vector<int> a;

int consistency1(int n){

	vector<int> dp(n+1, INF);
	dp[0] = 0;
	if(a[0] == 0) dp[1] = 0;
	else dp[1] = 1;
	
	for(int i=2; i<=n; i++){
		
		int j = i-1;
		while(j>=0){
			
			if(a[j]+1 == i-j){
				dp[i] = min(dp[i], dp[j]);
			}
			else dp[i] = min(dp[i], dp[j] + i-j);
			j--;
		}
		
	}
	
	return dp[n];
}




//* APproach 2 : 

int consistency2(int n){

	vector<int> dp(n+1, INF);
	dp[0] = 0;
	if(a[0] == 0) dp[1] = 0;
	else dp[1] = 1;
	
	for(int i=2; i<=n; i++){
		
		int j = i-1;
		while(j>=0){
			
			if(a[j]+1 == i-j){
				dp[i] = min(dp[i], dp[j] + 0);
			}
			j--;
		}
		
		dp[i] = min(dp[i], dp[i-1]+1);
		
	}
	
	return dp[n];
}





int consistency3(int n) {
    vector<int> dp(n + 1, INF);
    dp[0] = 0;
    
    if (a[0] == 0) dp[1] = 0;
    else dp[1] = 1;
    
    unordered_map<int, int> mp = {{a[0] + 1, dp[0]}};
    
    for (int i = 2; i <= n; i++) {
        
        if (mp.count(i)) {
            dp[i] = mp[i];
        }
        
        dp[i] = min(dp[i], dp[i-1] + 1);
        
        if (mp.count(a[i-1]+i)) {
            mp[a[i-1]+i] = min(mp[a[i-1]+i], dp[i-1]);
        } else {
            mp[a[i-1]+i] = dp[i-1];
        }
    }
    
    return dp[n];
}




//? Approach 3 : Backwards 


int consistency4(int n) {
    vector<int> dp(n + 1, INF);
    dp[0] = 0;
    

    
    return dp[n];
}










int practice(int n){


    return 0;
}





void solve() {
    
    int n;
    cin>> n;
    
    a.resize(n);
    for(int i=0; i<n; i++) cin >> a[i];
    
    cout << consistency1(n) << " " << consistency2(n) << " " << consistency3(n) << " " << consistency4(n) << endl;


}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}