#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c = 0;
  string s;
  cin >> a >> b;
  cin >> s;
  bool flag = false;
  if (s[a] == '-') {
    for (int i = 0; i < s.size(); i++) {
      if (s[i] >= '0' && s[i] <= '9' || s[i] == '-') {
        c++;
      }
    }
    if (c == s.length()) {
      flag = true;
    }
  }
  if (flag) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
