#include <string>
#include <iostream>
using namespace std;

bool isNum(char x){
	return '0' <= x and x<='9';
}

int main(){
  int a,b; cin >> a >> b;
  string s; cin >> s;
  string ans="Yes";
  for(int i=0;i<s.length();i++){
  	if(i==a){
    	if(s[i]=='-') continue;
       else ans="No";
    }
    else{
      if(isNum(s[i]) continue;
      else ans="No";    
    }
  }
  cout << ans << endl;
 return 0;
  
}