#include <bits/stdc++.h>
using namespace std;
struct edge {
  int from, to;
};
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool flag = true;
  for (int i = 0; i < s.size(); i++) {
    if ((0 <= i && i < a) || (a + 1 <= i && i < b)) {
      if ('0' > s[i] || s[i] > '9') flag = false;
    }
    if (i == a) {
      if (s[i] != '-') flag = false;
    }
  }
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
