# include<stdio.h> # include<vector> # include<iostream> # include<algorithm> # include<set> # include<map> # include<string> using namespace std; int main(){ int n,m; char b[10000]; cin>>n>>m; for(int i=0;i<n;i++){ cin>>b[i]; if(b[i]=='u'&&m!=0){ m-=1; }if(b[i]=='d'&&m!=n){ m+=1; } }cout<<m; }