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//Wiktor Kotala
#include <bits/stdc++.h>
#define f first
#define s second
#define add push_back
using namespace std;
typedef long long ll;
typedef pair<int,int> pint;
typedef pair<ll,ll> pll;
const int inf = 1'000'000'001;
vector<int> V;

int solve(){
    vector<int> lens;
    int dlugosc = 0, Vs = V.size();
    bool rosnie = 1;

    for(int i=0; i<Vs-1; i++){
        if((rosnie && V[i] < V[i+1]) || (!rosnie && V[i] > V[i+1])){
            lens.add(dlugosc);
            dlugosc = 0;
        }
        else{
            dlugosc++;
        }
        rosnie = !rosnie;
    }
    lens.add(dlugosc);

    int odp = 0;
    for(const int& len : lens){
        odp += (len+1) / 2;
    }
    return odp;
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int n, a;

    cin >> n;
    for(int i=0; i<n; i++){
        cin >> a;
        V.add(a);
    }

    int ans = solve();
    V.insert(V.begin(), -inf);
    cout << min(ans, solve());
	return 0;
}