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#include <iostream>
using namespace std;


long long arr[1000001];
int res=0, res2=0;

void solve(){
    int n, x=0;
    cin>>n;
    for(int i=1; i<=n; i++)cin>>arr[i];
    for(int i=2; i<=n; i++){
        if(arr[i-1]<=arr[i] && x==0){res++; i++; continue;}
        if(arr[i-1]>=arr[i] && x==1){res++; i++; continue;}
        x^=1;
    }
    x=1;
    for(int i=2; i<=n; i++){
        if(arr[i-1]<=arr[i] && x==0){res2++; i++; continue;}
        if(arr[i-1]>=arr[i] && x==1){res2++; i++; continue;}
        x^=1;
    }

    cout<<min(res, res2);

}



int main()
{
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);
    solve();
    return 0;
}