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