
#include <string>
using namespace std;
int a,b;
string s;
int main(){
    cin>>a>>b;
   cin >> s;
    for(int i=0;i<a+b+1;i++){
      if( i ==a){
        if(s[a]!='-'){
          cout << "No" << endl;
          return 0;
        }
        else if( !(s[i] >= 0&& s[i] <=9)){
          cout << "No" << endl;
          return 0;
        }
      }
    }
cout << "Yes" << endl;
}