#include <bits/stdc++.h>
using namespace std;
char s[15];
int main() {
  int a, b;
  cin >> a >> b;
  for (int i = 0; i < a + b + 1; i++) {
    s[i] = getchar();
    if (i != a) {
      if (s[i] < '0' || s[i] > '9') {
        cout << "No";
        return 0;
      }
    } else {
      if (s[i] != '-') {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
}
