#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b;
  cin >> s;
  int l = s.length();
  if (l == a + b + 1) {
    if (s[a] == '-') {
      int flag = 0;
      for (int i = 0; i < a; i++) {
        if (s[i] == '0' || s[i] == '1' || s[i] == '2' || s[i] == '3' ||
            s[i] == '4' || s[i] == '5' || s[i] == '6' || s[i] == '7' ||
            s[i] == '8' || s[i] == '9')
          continue;
        else
          flag = 1;
      }
      for (int i = a + 1; i < b; i++) {
        if (s[i] == '0' || s[i] == '1' || s[i] == '2' || s[i] == '3' ||
            s[i] == '4' || s[i] == '5' || s[i] == '6' || s[i] == '7' ||
            s[i] == '8' || s[i] == '9')
          continue;
        else
          flag = 1;
      }
      if (flag == 0)
        cout << "Yes" << endl;
      else
        cout << "No" << endl;
    } else
      cout << "No" << endl;
  } else
    cout << "No" << endl;
  return 0;
}
