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