#include <bits/stdc++.h>
using namespace std;

int main() {
  int A, B;
  string S;
  cin >> A >> B >> S;

  string ans = "Yes";

  for (int i = 0; i < A + B + 1; i++) {
    if (i != A && S.at(i) == '-') ans = "No";
    if (i == A && S.at(i) != '-') ans = "No";
  }

  cout << ans << endl;
}