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