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