#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  bool cnt = false;
  cin >> A >> B;
  string s;
  cin >> s;
  for (int i = 0; i <= A; i++) {
    if (s.at(i) != '-') {
      cnt = false;
    } else {
      cnt = true;
      break;
    }
  }
  if (s.at(A + 1) != '-') {
    cnt = true;
  }
  for (int i = A + 2; i <= A + B + 1; i++) {
    if (s.at(i) == '-') {
      cnt = true;
      break;
    }
  }
  if (cnt == true) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  return 0;
}
