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#include <iostream>
using namespace std;
constexpr int N = 50004, MIN = -1e9, MAX = 1e9;
int n, tab[N], tab2[N], out, out2;
bool rise = true, rise2 = true;
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n;
    for (int i = 0; i < n; i++){
        cin>>tab[i];
        tab2[i] = tab[i];
    }
    
    for (int i = 0; i < n - 1; i++) {
        if(rise){
            if(tab[i] <= tab[i+1]){
                out++;
                tab[i+1] = MIN;
            }
            rise = false;
        }else{
            if(tab[i] >= tab[i+1]){
                out++;
                tab[i+1] = MAX;
            }
            rise = true;
        }
        
        if(rise2){
            if(tab2[i] >= tab2[i+1]){
                out2++;
                tab2[i+1] = MAX;
            }
            rise2 = false;
        }else{
            if(tab2[i] <= tab2[i+1]){
                out2++;
                tab2[i+1] = MIN;
            }
            rise2 = true;
        }
        
    }
    cout<<min(out, out2)<<"\n";
    return 0;
}