#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  int N = a + b + 1;
  bool can = false;
  if (N == s.size()) {
    for (int i = 0; i < (N - 1); i++) {
      if (s[i] == '-') can = false;
      if (s[a] == '-') can = true;
    }
  }
  if (can)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
