#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>


int main() {
    // store number of steps taken
    int num_steps;
    std::cin >> num_steps;
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');


    int num_valleys = 0;
    int position = 0;
    char step_direction;

    // determine number of valleys
    for (int i = 0; i < num_steps; ++i) {
        std::cin >> step_direction;
        // keep track of "downs"
        if (step_direction == 'D') {
            if (position - 1 == -1) {
                ++num_valleys;
                --position;
            } else {
                --position;
            }
        } else if (step_direction == 'U') {
            ++position;
        }
    }

    // print number of valleys
    std::cout << num_valleys;

    return 0;
}