#include<iostream>
using namespace std;

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