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