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#define pb push_back
#define mp make_pair
#define fi first
#define se second 
#define all(...) begin(__VA_ARGS__) , end(__VA_ARGS__)
#define boost {ios_base::sync_with_stdio(false); cin.tie(); cout.tie();}
 
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector <int> vi;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
constexpr ll nax = 2e5+6969, INF = 2e9+6969;

int n, t[nax];
 
int main()
{
    scanf("%d", &n);
    for(int i=0;i<n;i++) {
        scanf("%d", &t[i]);
    }

    int ans = n, cur = 0;
    bool big = 0;
    for(int tur = 0; tur < 2; tur++) {
        for(int i=1;i<n;i++) {
            if(big) { 
                if(t[i] <= t[i-1]) {
                    cur++;
                    big ^= 1;
                    i++;
                }
            }
            else {
                if(t[i] >= t[i-1]) {
                    cur++;
                    big ^= 1;
                    i++;
                }
            }
            big ^= 1;
        }
        ans = min(ans, cur);
        // printf("%d\n", ans);
        cur = 0;
        big = 1;
    }
    printf("%d\n", ans);

	return 0;
}