#include<bits/stdc++.h>
using namespace std;
int main(){
  int i,A,B;cin>>A>>B;
  string ss;cin>>ss;
  if(ss[A]=='-'){
    ss[A]='0';
  }else{
    cout<<"No";
    return 0;
  }
  for(i=0;i<=A+B;i++){
    if(ss[i]=='-'){
      cout<<"No";
      return 0;
    }
  }
  cout <<"Yes";}