#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string S;
  bool d = true;
  cin >> a >> b >> S;
  for (int i = 0; i < S.size(); i++) {
    if (i != a) {
      if (S[i] < '0' || S[i] > '9') d = false;
      break;
    }
    if (i == a) {
      if (S[i] != '-') d = false;
      break;
    }
  }
  if (d) cout << "Yes" << endl;
  if (!(d)) cout << "No" << endl;
}
