#include<iostream> #include<cstring> #include<string> using namespace std; int main(){ int n,m; cin>>n>>m; string s; getline(cin,s); for(int i=0;i<s.size();++i){ if(s[i]=='u'&&m>0) --m; else if(s[i]=='d'&&m<n) ++m; } cout<<m; return 0; }