#include <bits/stdc++.h>
#define int long long
using namespace std;

signed main() {
  int a,b;
  string s;
  int k=0;
  cin>>a>>b>>s;
  for(int i=0;i<a+b+1;i++){
    if(i==a){if(s[i]!='-')k++;}
    else{if((int)s[i]<48||(int)s[i]>57)k++;}
  }
  if(k)cout<<"No"<<endl;
  else cout<<"Yes"<<endl;
}
