#include<bits/stdc++.h>
using namespace std;
int main(){
  int a,b,d=1,e=0,f=1;
  string c;
  cin>>a>>b>>c;
  for(int i=0;i<=a+b;i++){
    if(i<a) if(c[i]=='-') d=0;	
    if(i==a) if(c[i]=='-') e=1;
    if(a<i) if(c[i]=='-') f=0;
  }
  if(d+e+f==3) cout<<"Yes";
  else cout<<"No";
  cout<<"\n";
}