#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  char s[200];
  cin >> s;
  for (int i = 0; i < strlen(s); i++) {
    if (i == a && s[i] != '-') {
      cout << "No";
      return 0;
    } else if (s[i] >= '0' && s[i] <= '9') {
      cout << "No";
      return 0;
    }
  }
  cout << "Yes";
}
