#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1},
          dy[] = {1, 0, -1, 0, 1, -1, -1, 1};
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  string S;
  int A, B;
  cin >> A >> B;
  cin >> S;
  if (S[A] != '-') {
    cout << "No" << endl;
    return 0;
  }
  if (S.length() == A + B + 1) {
    cout << "Yes" << endl;
  }
}
