#include <bits/stdc++.h>
using namespace std;
int solve(string str) {
    int res = 0;
    int lap = 1;
    for (int i = 0; i < str.length(); i++) {
        if (str[i] == str[i+1]) {
            lap++;
        }
        else {
            res += lap / 2;
            lap = 1;
        }
    }
    return res;
}
int main() {
    int t;
    cin >> t;
    string s = "";
    while(t--) {
        char chr;
        cin >> chr;
        s += chr;
    }
    cout << solve(s);
    return 0;
}

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MTcKRERUVlZURFZWVlRWVlREVlY=

17
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