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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int n;
    cin >> n;
    char ch;
    int sea_level = 0;
    int count_valley = 0;
    for (int i = 1;i <= n; i++) {
        cin >> ch;
        if (ch == 'U' || ch == 'u') sea_level++;
        else if (ch == 'D' || ch == 'd') {
            sea_level--;
            if (sea_level == -1) count_valley++; // lembah baru
        }
        //cout << sea_level << endl;
        
    } 
    cout << count_valley << endl;
    return 0;
}