#include <bits/stdc++.h>
using namespace std;
int main() {
  int a = 0, b = 0, i = 0;
  string add = "";
  scanf("%d%d", &a, &b);
  cin >> add;
  for (i = 0; i < add.size(); ++i) {
    if (add[i] >= 48 && add[i] <= 57)
      continue;
    else {
      cout << "No\n";
      return 0;
    }
  }
  add[a] == '-' ? printf("Yes\n") : printf("No\n");
  return 0;
}
