#include <bits/stdc++.h>
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;
ll gcd(ll n, ll m) {
  ll tmp;
  while (m != 0) {
    tmp = n % m;
    n = m;
    m = tmp;
  }
  return n;
}
ll lcm(ll n, ll m) { return abs(n * m) / gcd(n, m); }
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;
}
using namespace std;
void solve() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int n = s.size();
  bool ng = false;
  for (int i = (int)0; i < (int)a; ++i) {
    if (s[i] == '-') ng = true;
  }
  for (int i = b; i < n; ++i)
    if (s[i] == '-') ng = true;
  if (s[a] != '-') ng = true;
  if (ng)
    cout << "No";
  else
    cout << "Yes";
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
