#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  int d = 0;
  string str1;
  cin >> a >> b;
  cin >> str1;
  for (int i = 0; i < a; ++i) {
    if (str1[i] == '-') {
      d += 1;
    }
    for (int j = a + 1; j < b; ++j) {
      if (str1[j] == '-') {
        d += 1;
      }
    }
  }
  if (str1[a] == '-') {
  } else {
    d += 1;
  }
  if (d > 0) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  return 0;
}
