#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  char arr[15];
  scanf("%d %d ", &a, &b);
  cin >> arr;
  bool ans = false;
  int siz = strlen(arr);
  if (arr[a] == 45) {
    for (int i = a + 1; i < siz; i++) {
      if (arr[i] >= '0' && arr[i] <= '9') {
        ans = true;
      } else {
        ans = false;
        break;
      }
    }
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
