#include<iostream>
using namespace std;

int main(){
  int a,b;cin>>a>>b;
  string n;cin>>n;
  int m=0;
  for(int i=0;i<a+b,i++){
    if(n[i]=='-')m++;
  }
  if(n[a]!='-'||n[b+1]!=' '||m>1)cout<<"No"<<endl;
  else cout<<"Yes"<<endl;
}
