#include <bits/stdc++.h>
using namespace std;
template <class T, class U>
ostream& operator<<(ostream& out, pair<T, U> c) {
  out << "(" << c.first << " ";
  out << c.second << ")";
  return out;
}
template <class T>
ostream& operator<<(ostream& out, vector<T> c) {
  for (auto it = c.begin(); it != c.end(); ++it) {
    if (it != c.begin()) out << " ";
    out << *it;
  }
  return out;
}
template <class T>
ostream& operator<<(ostream& out, set<T> c) {
  for (auto it = c.begin(); it != c.end(); ++it) {
    if (it != c.begin()) out << " ";
    out << *it;
  }
  return out;
}
const double PI = 3.141592653589793238463;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool t = true;
  if (s[a] != '-') {
    t = false;
  }
  for (int i = 0; i < a; i++) {
    if (s[i] < '0' && s[i] > '9') {
      t = false;
    }
  }
  for (int i = a + 1; i < a + b + 1; i++) {
    if (s[i] < '0' && s[i] > '9') {
      t = false;
    }
  }
  if (t) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
