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