#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<long long int>>;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
const long long INF = 1LL << 60;
int main() {
  long long int a, b;
  string s;
  cin >> a >> b >> s;
  for (long long int i = 0; i <= a + b; i++) {
    if (i == a && s[i] != '-') {
      cout << "No" << endl;
      return 0;
    }
    if (i != a && s[i] == '-') {
      cout << "Yes" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}
