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#include <cstdio>
#include <cstring>
#include <cmath>
#include <cassert>
#include <iostream>
#include <algorithm>
#include <iterator>
#include <string>
#include <vector>
#include <queue>
#include <bitset>
#include <utility>
#include <stack>

using namespace std;
typedef long long LL;
typedef pair<int,int> PII;
typedef vector<int> VI;
#define MP make_pair
#define FOR(v,p,k) for(int v=(p);v<=(k);++v)
#define FORD(v,p,k) for(int v=(p);v>=(k);--v)
#define REP(i,n) for(int i=0;i<(n);++i)
#define VAR(v,i) __typeof(i) v=(i)
#define FOREACH(i,c) for(VAR(i,(c).begin());i!=(c).end();++i)
#define PB push_back
#define ST first
#define ND second
#define SIZE(x) (int)x.size()
#define ALL(c) c.begin(),c.end()

#define ODD(x) ((x)%2)
#define EVEN(x) (!(ODD(x)))

int main() {
    int n;
    scanf("%d", &n);
    VI t;
    t.reserve(n);
    REP(i, n) {
        int tt;
        scanf("%d", &tt);
        t.PB(tt);
    }

    //changed, is_bigger
    vector<VI> dp = {{0,0}, {1,1}};//after 1 part
    vector<VI> new_dp = {{0,0}, {0,0}};

    FOR(i, 1, n-1) {
        int a = t[i-1], b = t[i]; 

        if (a == b) {
            new_dp[0][0] = dp[1][1];
            new_dp[0][1] = dp[1][0];
            new_dp[1][0] = min(dp[1][1], dp[0][1]) + 1;
            new_dp[1][1] = min(dp[1][0], dp[0][0]) + 1;
        } else if (a > b) {
            new_dp[0][0] = min(dp[0][1], dp[1][1]);
            new_dp[0][1] = dp[1][0];
            new_dp[1][0] = min(dp[1][1], dp[0][1]) + 1;
            new_dp[1][1] = min(dp[1][0], dp[0][0]) + 1;
        } else {// a < b
            new_dp[0][0] = dp[1][1];
            new_dp[0][1] = min(dp[0][0], dp[1][0]);

            new_dp[1][0] = min(dp[1][1], dp[0][1]) + 1;
            new_dp[1][1] = min(dp[1][0], dp[0][0]) + 1;

        }
        swap(new_dp, dp);
    }
    int res = 1000000000;
    REP(changed, 2) REP(is_bigger, 2) res = min(res, dp[changed][is_bigger]);

    printf("%d\n", res);
    return 0;
}