#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int to_depth(char s)
{
    return s == 'D' ? -1 : 1;
}

int main() {
    int n;
    cin >> n;
    int depth= 0;
    int valleys= 0;
    for (int i= 0; i < n; ++i) {
        char s;
        cin >> s;
        depth+= s == 'D' ? -1 : 1;
        if (depth == -1 && s == 'D')
            valleys++;
    }
    cout << valleys << endl;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}