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