#include <iostream>
using namespace std;
int main() {
int n,i,contor=0,v[100];
//Citire date
cin >> n;
for (i = 0; i < n; i++)
cin >> v[i];
//Parcurgere si contorizare
for (i = 0; i < n - 1; i++)
if (v[i] % 10 == v[i + 1] % 10)contor++;
//Afisare solutie
cout << contor;
}
#include <iostream>
using namespace std;
int main() {
int n,i,contor=0,v[100];
//Citire date
cin >> n;
for (i = 0; i < n; i++)
cin >> v[i];
//Parcurgere si contorizare
for (i = 0; i < n - 2; i++)
if (v[i] < v[i + 1] && v[i + 1] < v[i + 2])contor++;
//Afisare solutie
cout << contor;
}