#include<bits/stdc++.h>
using namespace std;
int f[109][109];
 
int main()
{
   int a,b;
   string s;
   cin>>a>>b;
   cin>>s;
   int fl=1;
   for(int i=0; i<s.size(); i++)
   {
       if(i==a && s[i]!='-' || i!=a && s[i]=='-') {fl=0;}
   }
   if(fl) cout<<"Yes"<<endl;
   else cout<<"No"<<endl;
 
}