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