#include<iostream>
using namespace std;
int main(){
  int A,B,flag=0;
  string S;
  cin >> A >> B;
  cin >> S;
  for(int i=0;i<=A+B;i++){
    if((i==A && S.at(i)!='-') || (i!=A && S.at(i)=='-')){
      flag=1;
      break;
    }
  }
  if(flag==1)cout << "No" << endl;
  else cout << "Yes" << endl;
}