#include <bits/stdc++.h>
using  namespace  std;
using ll=long long;
int main(){
int a,b;
string s;
cin>>a>>b>>s;
bool flag=true;
for(int i=0;i<=a+b;i++){
  if(i==a&&s.at(i)!='-')flag=false;
  else if(s.at(i)=='-')flag false;
}
if(flag)cout<<"Yes"<<endl;
else cout<<"No"<<endl;
}
