#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int A,B;cin>>A>>B;
  string S;cin>>S;
  string ans="Yes";
  for(int i=0; i<S.size(); i++){
    if(i==A){
      if(S[i]!='-')ans="No";
    }else{
      if(S[i]<'0'||S[i]>'9')ans="No";
    }
  }
  cout<<ans<<endl;
}