#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 steps,lvl=0,init=0,valleys=0;
    string hike;
    cin >> steps;
    cin >> hike;
    for(int i=0;i<steps;i++){
        if(lvl==0 && hike[i]=='D'){
            init=1;
        }
        if(init && lvl==-1 && hike[i]=='U'){
            valleys++;
            init=0;
        }
        if(hike[i]=='U'){
            lvl++;
        }else{
            lvl--;
        }
    }
    cout << valleys <<endl;
    return 0;
}