#include <fstream>
using namespace std; 
int main ()
{
    int i,N,aux,k=0;
    char a[10000] ;
    ifstream f("litere.in") ;
    ofstream g("litere.out") ;
    f>>N ;
    for (i=0;i<=N;i++)
    f>>a[i] ;
    if (a[i]>a[i+1])
    {
    k++ ;
    aux=a[i] ;
    a[i]=a[i+1] ;
    a[i+1]=aux ;
}
g<<k;
f.close() ;
g.close() ;
return 0;
}