#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  cin >> A >> B;
  string S;
  cin >> S;
  bool ans = true;
  for (int i = 0; i < S.size(); i++) {
    if (i == A) {
      if (S[i] != '-') ans = false;
    } else {
      if (!(S[i] >= 'a' && S[i] <= 'z')) ans = false;
    }
  }
  if (ans) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
