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