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

int main(){
  int A, B;
  string S;
  cin >> A >> B >> S;
  if ( S[A+1] == "-" && S![A+1] != "-"){
    cout << "Yes" << endl;
  } else{
    cout << "No" << endl;
  }
  return 0;
}
