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


int main() {
    int n;
    cin >> n;
    
    int current = 0, valleys = 0;
    char value;
    for(int i = 0; i < n; i++){
        cin >> value;
        if( value == 'D'){
            if( current == 0 ){
                valleys++;
            }
            current--;
        }else if( value == 'U'){
            current++;
        }
    }
    
    cout << valleys;
    return 0;
}