#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  cin >> A >> B;
  string S;
  cin >> S;
  int count = 0;
  for (int i = 0; i < S.size(); i++) {
    if (S[i] == '-') {
      count++;
    }
  }
  if (count == 1) {
    cout << "Yes";
  } else {
    cout << "No";
  }
}
