// https://www.hackerrank.com/contests/rookierank/challenges/counting-valleys

#include <cstdio>

int main()
{
    int n, valley=0, pos=0;
    char c;
    bool flag=false;
    scanf("%d", &n);
    getchar();
    while(n--)
    {
        scanf("%c", &c);
        if(c=='D')
        {
            if(pos==0)
                flag=true;
            pos--;
            if(flag)
            {
                valley++;
                flag=false;
            }
        }
        else if(c=='U')
            pos++;
    }

    printf("%d\n", valley);

    return 0;
}