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


int main()
{
    int N;
    cin >> N;
    int pos = 0;
    int valleys = 0;
    
    for (int i = 0; i < N; i++)
    {
        char input;
        cin >> input;
        
        if (input == 'D')
        {
            pos--;
        }
        else
        {
            if (pos == -1)
            {
                valleys++;
            }
            pos++;
        }
    }
    
    cout << valleys << "\n";
    return 0;
}