#include <bits/stdc++.h>
using namespace std;
char a[11];
int i, m, j, k, n;
int main() {
  cin >> m >> n;
  gets(a);
  for (i = 1; i <= m + n + 1; i++) {
    if (i != m + 1) {
      if (a[i] < '0' || a[i] > '9') {
        cout << "No";
        return 0;
      }
    }
    if (i == m + 1 && a[i] != '-') {
      cout << "No";
      return 0;
    }
  }
  cout << "Yes";
  return 0;
}
